1 1 United States Department of Commerce

I \lBI National Institute of Standards and Technology

NISTIR 90-3937

SCANNING SYSTEM FOR

MEASURING UNIFORMITY OF

LASER DETECTOR RESPONSE AND

LASER BEAM DIMENSIONS

A.L. Rasmussen

W.E. Case

A.A. Sanders

QC

100

. U56

90-3937

1990
NATIONAL INSTITUTE OF STANDARDS &

TECHNOLOGY

Research Mormatk® Center

Gaithersburg, MD 20899

DATE DUE

Demco, Inc. 38-293
NISTIR 90-3937

SCANNING SYSTEM FOR

MEASURING UNIFORMITY OF

LASER DETECTOR RESPONSE AND

LASER BEAM DIMENSIONS

A.L. Rasmussen

W.E. Case

A.A. Sanders

Electromagnetic Technology Division

Center for Electronics and Electrical Engineering

National Engineering Laboratory

National Institute of Standards and Technology

Boulder, Colorado 80303-3328

April 1990

U.S. DEPARTMENT OF COMMERCE, Robert A. Mosbacher, Secretary

NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY, John W. Lyons, Director

CONTENTS

Page

Abstract 1

1. Introduction 1

2. System Layout and Interfacing Parts 3

3. Software 4

4. Measurement Procedures, Examples, and Applications 5

5. Conclusion 7

6 . Acknowledgments 7

7. References 7

8. Figures 7-13

Appendix A: Monitor specifications 14

Appendix B: A/D converter boards and amplifiers attached to

monitor and unknown detector 15

Appendix C: Home coordinates, step, and feedrate of the unknown

detector or the pinhole attached to a detector 16

Appendix D: Pinholes, X and Y scale limits, and Z adjustment

along optical axis 18

Appendix E: System equations 19

Appendix F: Procedures and menus for surfer graphics 22

Appendix G: Examples of graphics 42

Appendix H: Graphics interface program description 78

Appendix I: Placing the unknown detector in the (m=0) or (m=2)

beams of the beam splitter wedge 85

Appendix J: Linear detector for the visible and near infrared

laser wavelengths 86

iii
DISCLAIMER

Certain commercial equipment, instruments, and materials are identified in this

publication in order to explain the experimental procedure adequately. Such

identification in no way implies approval, recommendation, or endorsement by the

National Institute of Standards and Technology, nor does it imply that the equipment,

instruments, or materials identified are necessarily the best available for the

purpose

.

1

V
Scanning System for Measuring Uniformity

of Laser Detector Response and Laser Beam Dimensions

A.L. Rasmussen, W.E. Case, and A. A. Sanders

Electromagnetic Technology Division

National Institute of Standards and Technology

Boulder, Colorado 80303-3328

A computer- controlled scanning system constructed at NIST/Boulder

moves a detector or a pinhole attached to a detector in a plane

perpendicular to the axis of a stationary laser beam. A linear

detector monitors the laser beam. The system measures the

uniformity of laser detector response and the laser beam dimensions.

The device to be measured is attached to computer controlled X-Y

translation tables that scan a maximum area of 15 cm x 15 cm with

10 -4 cm resolution along each axis. Detector and monitor outputs are

digitized with a computer board. Output versus position is

represented in contour maps and surface graphics on the computer,

the plotter, or the printer. Choice of matrix dimensions and step

sizes of the scanned area determine the resolution of graphics.

Maximum, minimum, average and variance data of the Z output of a

detector for a chosen X-Y area provide additional uniformity

information. High precision fiber couplers can be used to spatially

filter and/or collimate the beam. Available sources are

conventional lasers from the visible and the near infrared

wavelengths or laser diodes at 0.82, 1.3 and 1.55 /im wavelengths.

A precision positioner along the optical axis moves the measurement

device and controls the size of the beam entering it. Beam

dimensions and detector response data are given. This report

documents the use of the system to calibrate detectors.

Key words: beam dimensions; computer-controlled scanning system;

detector and beam graphics; detector and beam scanning; laser

detector response; laser power monitor; linear detector; uniformity

1. Introduction

The reliability of detector calibration depends upon the uniformity of detector

response and the dimensions of the interacting laser beam. This report describes

a computer-controlled scanning system for measuring these parameters.

1
Appendixes A through J present many important details needed to understand and

use the system. Appendix J describes the linear detector (ROSY 7-1) that

monitors the detector under calibration in the scanning system.

The device to be measured is scanned in a plane perpendicular to the axis of a

stationary laser beam. Software using output and position data give (1) surface

graphics and information, and (2) beam radius and shape [1]. To determine

linearity, measurements are made at two or more power densities. The user may

determine experimentally the effect of changing beam size on uniformity

measurements

.

Uniformity scans in this report fluctuated more for smaller beams than larger

ones. They were smoothed and rounded for beams larger than coordinate steps.

The scanning system provides greater control and information of the beam and

detector surface than the system in which rotating mirrors scan the beam over

the detector surface [2], In the latter system, an oscilloscope plots the

response of the surface.

The remainder of this report describes:

2. System Layout and Interfacing Parts

3. Software

4. Measurement Procedures, Examples, and Applications

5. Conclusions

6 . Acknowledgments

7. References

8. Figures

9. Appendixes

2
2. System Layout and Interfacing Parts

The computer- controlled scanning system measures the uniformity of laser detector

response and the laser beam dimensions. The system layout and interfacing are

described in figures 1-6. These figures show a system that delivers a laser beam

to a monitor and detector and digitizes the outputs, and a computer that controls

the detector motion in a laser beam and provides two or three dimensional

graphics and surface response.

The various parts of the system in figures 1-6 are now discussed. Conventional

and diode laser sources are available. A spatial filter and collimator are

mounted in two high-precision fiber couplers. A microscope objective focuses

a laser beam into one end of a single -mode or multimode fiber, and the beam at

the other end of the fiber is collimated with a microscope objective [3] . These

components are by-passed when the laser beam is usable without them. Each laser

diode pigtail output enters a microscope objective suitable for the wavelength

to collimate the beam. The multiplexer, in front of a microscope objective,

passes either of two laser diode beams. A mirror moved into the system directs

the diode beam into the beam splitter wedge. Two irises through which the main

beam passes are used to align the laser along an optical axis.

The wedge beams are identified as follows: transmitted beam (m=0) , beam reflected

from the back surface (m=+l) , and beam reflected from the back and front surfaces

(m=2) . A 2° beam splitter wedge reflects the (m=+l) beam into the monitor and

also transmits the (m=2) or (m=0) beam through a microscope objective, suitable

for the wavelength, into the detector or pinhole attached to a detector.

A Z adjustment micrometer along the optical axis controls the distance between

the microscope objective and the measurement device and, consequently, the size

of the beam entering it. The micrometer and measurement device are attached to

the X and Y linear translational tables of the scanner.

A motion controller directs scanner motion (see figure 2, Interfacing of scanning

system). By use of the joystick, the operator may determine home coordinates

3
for the measurement device. The computer interfaces the motion controller

through program Unidex, the National GPIB card, QuickBASIC 4.0, and the IEEE Bus.

Following the monitor and measurement device are precision amplifiers for

measuring low voltages. The amplifiers feed A/D converter boards that are

connected to the computer. The boards have pseudodifferential termination

without grounding and a ± 10 V scale at channel 1 for the monitor and ± 10,

± 1, ± 0.1, or ± 0.02 V scale at channel 0 for the measurement device. Theamplifiers may be omitted if the gain of the boards is adequate to amplify the

signals

.

The computer records the monitor output and the measurement device output, and

X and Y positions in the beam. It controls the measurement process and data.

The software produces two -and three-dimensional graphics for the screen, printer,

or plotter. See appendixes F, G, and H for further descriptions.

3. Software

Three kinds of computer programs control motion and data processing of the

scanning system:

(1) Combine3.

This program works with the daughter board in the bipolar mode and is

meant for testing the equipment. It takes data, one point at a time, only

when prompted. You are able to choose the gain you need. It will take up

to 100 data points.

(2) ScanlOlO, Scan2525, Scan5050, and Scan6363.

These programs are used with the daughter board in the bipolar mode and read

off of an unknown and a monitor. You are able to choose the gain you need

on the unknown, but the monitor is default at 1. They give a 10x10,

25x25, 50x50, or 63x63 matrix of data [numbers in programs identify

4
matrix] . The program scans the unknown detector in a beam to determine its

uniformity

.

(3) 2525PIN0

.

This program is used with the daughter board in the bipolar mode, and reads

off of an unknown and a monitor. It is to scan a pinhole in a beam to

determine the beam radius and shape. It gives a 25x25 matrix.

The motion controller boot program is: Boot 25 G 7 [X and Y translational tables

go to coordinates 0,0].

4. Measurement Procedures, Examples, and Applications

The scanning system will measure uniformity of detector response below saturation

and beam dimensions. We recommend that you study sections 2 and 3 of this

report, the figures, and the appendix; they provide essential information on

system layout, interfacing, and procedures. Plan beam and detector measurements

for your device. It may take a number of runs to get the resolution, beam

dimensions, and detector measurements needed. Follow measurement procedures

below:

o

o

o

o

o

o

Turn on scanning equipment rack.

Select and run laser for warmup period before proceeding further.

Align beam through irises.

Spatially filter and/or collimate beam, when helpful, using the highprecision fiber couplers.

Align beam splitter wedge by reflecting the (m=2) beam (two

reflections in wedge) back on itself and superimposing the (m=3)

beam (three reflections in wedge) on the (m=2) beam. Use wedge

holder adjustments.

Connect the monitor and the device to be measured to the amplifiers

and terminal board attached to the daughter board without attaching

leads to a ground. See appendixes A and B.

5
o Check laser stability using monitor in program combine3. See

section 2.

o Determine home coordinates and step and feed rate for the unknown

detector or the pinhole attached to a detector. See appendixes C

and D

.

o Select computer program for the desired resolution and measurement.

See section 3.

o Turn the motion controller off and then on to reboot it.

o Turn out lights and start run.

o Plot and calculate data. See appendixes E, F, G, and H.

o Refer to appendixes and measurement examples to perform tasks,

o Check whether input power and detector output are linear by changing

power by a factor two or more.

o Refer to appendix I for changing beams into the unknown

detector

.

Measurement examples demonstrate some of the things the scanning system can do.

See appendixes F and G. They include two and three dimensional surfaces and

contour maps and data of beams and detector responses.

Beam radius is calculated using the 1/e 2 point and side views and contour maps

of the beam. Contours are plotted on an X-Y grid. See appendix G: Examples of

graphics

.

Measurement applications may include scanning sectionally or completely many

kinds of optical beams. Choices of measurements are broad because of the 15 cm

x 15 cm area; the 10~ A cm resolution; the gains of the nanovolt amplifier, of the

daughter board and of the computer software; and detector-pinhole-aperture

options

.

A laser power stabilizer may be needed to improve the precision of some

measurements

.

6
5.

Conclusion

The high-resolution, computer-controlled scanning system yields a detailed

evaluation of laser detector surface response and laser beam intensity. System

users may determine suitable beam dimensions for evaluating detector uniformity

and optical systems. Users may improve the system with software and various

modifications. Application of the scanning system can contribute to increased

understanding of the functioning of detectors and optical systems.

6 . Acknowledgments

The authors thank Lee Larson for writing program Unidex, using the National GPIB

card with QuickBASIC 4.0 to control the Unidex, the motion controller; David

Livigni for adapting the program for three dimensional surfaces and topographical

graphics of data; Daniel Habernal for setting up equipment and taking data;

Robert Juneau and Joe Skudler for designing and fabricating components of the

scanning system and the linear detector; Douglas L. Franzen and Tim Drapela

for their assistance on laser diodes and fiber optics; Eric Johnson and Matt

Young for their discussions on optics and optical electronics.

7. References

[1] Dickson, L.D. Ronchi ruling method for measuring Gaussian beam diameter.

Opt. Eng. 18 (1): 70, 1979 January-March

.

[2] Smith, R.L.; Phelan, R.J., Jr. Limitations of the use of vacuum photodiodes

in instruments for the measurement of laser power and energy. Appl. Opt. 12

(4) : 795; 1973 April.

[3] Oates, C.W.; Young, M. Microscope objectives, cover slips, and spherical

aberration. Appl. Opt. 26(11): 2043; 1987 June.

8

.

Figures

7
Figure 1 . Layout of scanning system for measuring

linearity and uniformity of laser detector

response and laser beam profile.

8
A/D

CONVERTER

BOARDS*

CHANNEL 1

NANOVOLT

AMPLIFIER

GAIN 10 z 10 3

, 104

, 10 6

MONITOR,

LINEARITY

TRANSFER

STANDARD

** PSEUDODIFFERENTIAL

TERMINATION

( +10, +1, +0.1, 1 0.02V)

Figure 2 Interfacing of scanning system.
Figure 3. Photograph of scanning system shows mirror holders, fiber

couplers, and HeNe and diode laser sources in the foreground;

monitor with back of chassis toward viewer, beam splitter with

dark frame, and scanner and joystick on the metal table in the

rear; nanovolt amplifiers and digital voltmeter on the table

to the right; and the terminal and daughter boards, the motion

controller, the computer, the printer, and the plotter in the

rack starting from the top shelf down. An arm (not shown) with

mirror attached to it may direct other laser beams into the

system.

10
Figure 4. Photograph of the scanning system shows fiber couplers,

mirror holders and HeNe and diode laser sources in the

foreground; and monitor with back of chassis toward viewer,

beam splitter with dark frame and scanner on the metal

table in the rear.

11
Figure 5. Photograph shows X-Y scanner with Z adjustment micrometer and

detector attached on the side. Absorber for capturing an

unused beam and microscope objective for controlling beam size

are in front of the scanner.

12
Figure 6 . Photograph of a portion of the scanning system shows Alvin

Rasmussen adjusting platform holding fiber couplers for laser

diode outputs. Near Rasmussen's right hand, structures with

small handles each move a mirror into the beam to direct it

to the scanner in the rear.

13
Appendix A: Monitor specifications

1. Readout: A/D card or voltmeter attached to a computer.

2. Nanovolt amplifier: gains 102

, 10 3, 10 4, and 10 5; 10 V maximum.

3. Detector: silicon PIN photodiode (Rosy 7-1), ~1 cm2 area, 100 ft and 1000 ft load, 0.4-1. 1 jum wavelength range.

4. Integrating sphere: cube with a 3.57 cm D sphere inside having a white

coating of barium sulfate, 0.766 cm inside D of entrance, -0.8 cm inside D

of exit, -0.2 throughput (decimal fraction of entrant energy emerging from

sphere), beam distributed uniformly on detector, baffle inside sphere stops

first reflection entering the detector.

5. Alignment parts: front surface mirror to reflect the beam on itself, iris

to center the beam into the detector.

6. Bias power supply: -180.0 V

7. Temperature controller: maintain temperature about 30 ± 0.1°C with a readout

of 3.9 kC.

8. Temperature controller power supply: 15 V

9. Positioner: with six degrees of freedom: align detector

14
Appendix B: A/D converter boards and amplifiers attached to monitor and unknown

detector

A/D converter: Lab Master DMA with PGL, product 811963.

Components: Terminal, daughter and mother boards connected in that

order

Terminal board:

Channel 0: Unknown detector; gain 1, 10, 100, 500 (gain setting 0, 1, 2,

3) ; bipolar

Channel 1: Monitor, gain 1 (gain setting 0), bipolar.

Daughter board: pseudodifferential (low terminal referred to a voltage without

ground)

Mother board: Inside computer.

Gain: Resolution* Gain Range Gainsetting

4.8828 mV 1 + 10 V 0

488.28 mV 10 + 1 V 1

48.828 /zV 100 + 0.1 V 2

9.7656 mV 500 + 0.02 V 3

Amplifiers: Nanovolt amplifier

Keithley 140

Gain: 102

, 10 3, 10\ 10 5 Uncertainty of gain: 0.01%

Manufacturer's values

15
Appendix C: Home coordinates, step, and feedrate for the unknown detector or

the pinhole attached to a detector

Manual control or joystick:

Set motion controller to [IMD] [SLW] for maximum speed of about 1

cm/sec. Set motion controller to [IMD] [F - n n n n n] [SLW] to set

any speed. [F-nnnnn] is a divisor with default value of 2 for

maximum speed and 65535 for minimum speed. The authors use the

default speed and gently push the joystick with + X = left and + Y

= down. These directions of motion make the beam appear to scan the

device rather than the device scan the beam.

Joystick used to find home coordinates of the detector and the beam:

1. Unknown detector home coordinates. Read the coordinates of the lower

left hand corner of the unknown detector on the motion controller.

2. Beam home coordinates. Read the coordinates of the pinhole with

maximum light passing through it on the motion controller. Use a

small mirror to observe the beam on the rear side of the pinhole.

Using the pinhole coordinates, estimate the coordinates of the lower

left corner of a square containing the beam.

3. Lower left corner coordinates will be smaller than the center ones.

Entering home coordinates in the program:

Place home coordinates in the programs as follows:

CMD1$ = " IG7*G0X(home coordinate) F(current value) Y(home coordinate)

F(current value)*G92X0Y0*G10"

.

Determining step and feedrate:

Estimate the area of the unknown detector or beam. Select the

resolution and the matrix needed. Divide by one of the factors of

the matrix to obtain the step size. Select a feed rate about the

same order of magnitude as the step size.

16
Examples of entering steps and feedrates in the programs and of the path of the

scan:

1. Unknown detector measurements

Use program SCAN2525. Enter X, Y, and F values.

Example

1000 CMD1$ = "IX500F2000D50"

2100 CMD1$ = " IX- 500F2000D50"

570 NEXT X

CMD1$ = "IY500F2000D50"

Programs with other matrices may be selected.

2 . Beam measurements

Use program 2525PIN0.

Enter X, Y, and F values.

Example

1000 CMD1$ = "IX5F10D50"

2100 CMD1$ = "IX-5F10D50"

570 NEXT X

CMD1$ = "IY5F10D50"

3. Path of the Scan

Repeats until XY matrix recovered.

Y

Start

17
Appendix D: Pinholes, X and Y scale limits, and Z adjustment along optical axis

Pinholes: Diameters 5, 10, 15, 25, 50, and 100 fim. Area about < 30% of beam

area

.

X and Y scale limits: These are the linear translation tables.

Resolution of X and Y, 1 /im; maximum X, 15 cm; maximum Y, 15 cm.

Z micrometer adjustment along optical axis:

Left revolution counter reads to 0.1 mm (accuracy 0.1 mm). Scale and right

vernier reads to 0.01 mm (accuracy 0.1 mm/m). Detector is attached to Z, which

is attached to the X and Y linear translation tables.

18
Appendix E: System equations

The power in the monitor WM is

where VM is the voltage of the monitor divided by the gain of the amplifier used

and CM is the calibration of the monitor in (V/W) with the monitor in the (m=+l)

beam of the beam splitter wedge. The wedge beams are identified as follows:

transmitted beam (m=0) , beam reflected from the back surface (m=+l) , and beam

reflected from the back and front surfaces (m=2) . From these designations, we

get ratios of beams such as appear in the text.

The power in the unknown Wu is

W = _Ym = Ym

u (m=+l ) CM (m=+l)

(m-2) (m=2)

where (m=+l)/(m=2) is the beam splitter ratio with the monitor in the (m=+l) beam

and the unknown in the (m=2) beam of the beam splitter wedge.

The calibration of the unknown Cu with the unknown in the (m=2) beam is

Vu

r (m=+l ) v„ M (m-2) - 34.66 • 12.27

vM

v

= 425.3

VM

where Cu is in (V/W) and Vu is the voltage of the unknown divided by the gain of

the amplifier used. CM = 34.66 V/W at 0.6328 /jm and (m=+l)/(m=2)=12 . 27 for SF6

glass (the composition of the beam splitter) at 0.6328 /tm.

Vu with the unknown in the (m=2) beam is

19
Cu Vm

425.3

Vu =

The equation may be used to determine whether Vu exceeds the scale limits of the

readout instrument.

The power in the unknown Wu is

TT . TT (m=0) VM (m=0) Wu - Wm -<£- "(m'^+X)

when (m=0)/(m=+l) is the beam splitter ratio with the unknown in the (m=0) beam

and the monitor in the (m=+l) beam of the beam splitter wedge.

The calibration of the unknown Cu with the unknown in (m=0) beam is

(m=0)

(m=+l)

34.66

12.27

2.825

where Cu is in (V/W) and Vu

’ is the volts of the unknown divided by the gain of

the amplifier used. CM = 34.66 V/W at 0.6328 fim and (m=0)/(m=+l) = 12.27 for

SF6 glass at 0.6328 fj,m.

Vu with the unknown in the (m=0) beam is

V

’ =

Cu VM

2.825

C„ =

V.

W,

= Yu

V,

. Yu

v.

V,

V,

The equation may be used to determine whether Vu exceeds the scale limits of the

readout instrument.

20
Finally

where P

and R

2 (Wu or Wu ')

P =

7T R

2

= the peak irradiance in W/cm2

= the radius in cm of the beam at the 1/e2 intensity.

21
Appendix F: Procedures and menus for surfer graphics

Explanation of menu choices for data:

1. Change Parameters.

To change run, axis, rotation, and tilt parameters.

2. View Surface.

To plot on screen.

3. Plot Surface.

To plot on printer or plotter depending upon output device selected in 11.

4. Raise Baseline.

To eliminate data below new baseline and to expand scale of remaining data.

5. Offset Data so that Lowest Point = 0.

6. Invert Data.

To change sign of data.

7. Calculate Mean and Deviation of Z-Data over present area.

To analyze data of a selected area.

8. Convert Data to Percentage of full Scale.

9. Restore Original Data.

10. Topographical Maps.

To make contour maps.

11. Change Output Device.

To change output device to either a printer or a plotter, LQ 1500 or 7440A

respectively

.

22
12. Enlarge Portion of Graph.

To observe details.

13. Print Run Information.

To accompany graphics and to review run information.

20. Exit.

To exit computer or to enter a program.

Examples of procedures and menus:

23
Application of graphics software follows data printout of run

613 -76.8324 -72.53242 -1622.355

614 -74.65448 -72. 53242 -1622. 355

615 -72.25034 -72.25034 -1622.355

616 -73. 79683 -72. 25034 -1622. 355

617 -73.29253 -72.25034 -1622.355

618 -72.67139 -72.25034 -1622. 355

619 -72.26373 -72.25034 -1622.355

620 -73. 38852 -72.25034 -1622. 355

621 -72.68532 -72.25034 -1622.355

622 -72.84615 -72. 25034 -1622.355

623 -72.89775 -72. 25034 -1622.355

624 -73. 29259 -72.25034 -1622. 355

625 -72.07173 -72.07173 -1622.355

mean of unknown =-1029.685

standard deviation= 720.

Percent standard deviation

5662

= Max = - 35. 26251

Min = “ 1573.761

0~stop

1-copy array data to printer

type number? ? 0

C : \ SOURCE > color 01,77

C: \ SOURCE) echo off

C : \ SOURCE > surf 1

Enter Input File Name (default = dump.): ?

Working. .

.

F inished

C : \ SOURCE > surf

2

C : \ SOURCE > echo off

24
Input Plot Title (default: ) ? 5-18-89 Run 7

Input X-Axis Label (default: “X-Axis" ) ?

Input Y-Axis Label (default: "Y-Axis" ) ?

Input 2-Axis Label (default: "Z-Axis" ) ?

Input Rotation About Z-Axis (default: 225 degrees) ?

Input Tilt After Rotation (default: 30 degrees) ?

Input the Number of Z-Axis Decimal Digits Displayed

(default: 3 )? 0

Input Z-Axis Scale Factor or A for Automatic

(default: Auto ) Suggested Value (Auto) = 0.015

7

Input Z-Axis Labeled Tick Spacing or A for Automatic

(default: AUTO ) ? 10

Plot Title = "5-18-89 Run 7"

X-Axis Label = "X-Axis"

Y-Axis Label = "Y-Axis"

Z-Axis Label = "Z-Axis"

Rotation About Z-Axis = 225

Tilt After Rotation = 30

Z-Axis Digits Displayed = 0

Z-Axis Scale Factor = Auto

Z-Tic Spacing = 10

Is This Correct (Y/n)

Input Date of Actual Run (default: ) ? 5-18-89

Amplifier Gain Setting (default: 0 ) ? 10

Input Laser Identifier (default: ) ? HeNe

Input Detector Identifier (default: ) ?• 4-8

Input Pinhole Identifier (default: ) ?

Run Date: 5-18-89

Gain: 10

Laser: HeNe

Detector: 4-8

Pinhole: none

Is This Correct? (Y/n)

25
Presently: Min-X

Min-Y

Min-Z

0 Max-X = 24

0 Max-Y =• 24

1 573 .761 Max-Z 35.26251

1. Change Parameters

2. View Surface

3. Plot Surface

4. Raise Baseline

5. Offset Data so that Lowest Point = 0

6. Invert Data

7. Calculate Mean and Deviation of Z-Data over Present Area

8. Convert Data to Percentage of Full Scale

9. Restore Original Data

10. Topographical Maps

11. Change Output Device

12. Enlarge Portion of Graph

13. Print Run Information

20. Exit

Input Number of Desired Option? 6

Reading: dump.grd Writing: dump2.grd

Presently: Min-X = 0 Max-X - 24

1. Change Parameters

2. View Surface

3. Plot Surface

4. Raise Baseline

5. Offset Data so that Lowest Point = 0

6. Invert Data

7. Calculate Mean and Deviation of Z-Data over Present Area

8. Convert Data to Percentage of Full Scale

9. Restore Original Data

10. Topographical Maps

11. Change Output Device

12. Enlarge Portion of Graph

13. Print Run Information

20. Exit

Min-Y

Min-Z

0 Max-Y = 24

35.26251 Max-Z 1573. 761

26
Input Number of Desired Option? 8

Reading: dump2„grd Writing: dump3.grd

Presently: Min--X = 0 Max-X = 24

Min--Y = 0 Max-Y - 24

Min--Z = 0 Max-Z = 100

1. Change Parameters

2. View Surface

3. Plot Surface

4. Raise Baseline

5. Offset Data so that Lowest Point = 0

6. Invert Data

7. Calculate Mean and Deviation of Z-Data over Present Area

8. Convert Data to Percentage of Full Scale

9. Restore Original Data

10. Topographical Maps

11. Change Output Device

12. Enlarge Portion of Graph

13. Print Run Information

20. Exit

Input Number of Desired Option? 3

PLOT Version 4.07

(C) Copyright Golden Software 1988

Press Ctrl-C to abort...

Do you wish to shift the entire plot? No

Do you wish to scale the entire plot? No

Optimizing SURFDATA. PLT for printer output... Please wait

Processing record number 1722

SURFDATA. OPT has been created

Position paper and press any key to plot SURFDATA . OPT ..."

Press any key to return to SURF.

27
Detector Measurement

28

- 1

8-

89

Run
Input Number of Desired Option? 4

Presently: Min~X 0 Max-X = 24

0 Max-Y = 24

50 flax-Z = 100

Min-Y

Min~Z

1 . Change Parameters

2. View Surface

3. Plot Surface

4- Raise Baseline

5. Offset Data so that Lowest Point = 0

6. Invert Data

7. Calculate Mean and Deviation of Z-Data over Present Area

8. Convert Data to Percentage of Full Scale

9. Restore Original Data

10. Topographical Maps

11. Change Output Device

12. Enlarge Portion of Graph

13. Print Run Information

20. Exit

Input Number of Desired Option?

29
Detector Measurement

30

1

8-

89

Run
Input Number of Desired Option? 4

Present Z-Values range from: 0 to 100

Input new minimum value for Z: 95

Reading: dump3.grd Writing: dump2.grd

Presently: Min-X - 0 Max-X = 24

Min-Y = 0 Max-Y = 24

Min-Z = 95 Max-Z = 100

1. Change Parameters

2. View Surface

3. Plot Surface

4. Raise Baseline

5. Offset Data so that Lowest Point = 0

6. Invert Data

7. Calculate Mean and Deviation of Z-Data over Present Area

8. Convert Data to Percentage of Full Scale

9. Restore Original Data

10. Topographical Maps

11. Change Output Device

12. Enlarge Portion of Graph

13. Print Run Information

20. Exit

31
D 0 -£ 0c.toi7 Measurement

sj *V~Z

32

5-18-89

Ru
Input Number of Desired Option? 1

Input Plot Title (default: "5-18-89 Run 7" ) ?

Input X-Axis Label (default: "X-Axis" ) ?

Input Y-Axis Label (default: "Y-Axis" ) ?

Input Z-Axis Label (default: "Z-Axis" ) ?

Input Rotation About Z-Axis (default: 225 degrees) ?

Input Tilt After Rotation (default: 30 degrees) ?

Input the Number of Z-Axis Decimal Digits Displayed

(default: 0 )? 3

Input Z-Axis Scale Factor or A for Automatic

(default: Auto ) Suggested Value (Auto) = 4.800

7

Input Z-Axis Labeled Tick Spacing or A for Automatic

(default: 10 ) ?

Plot Title = "5-18-89 Run 7"

X-Axis Label = "X-Axis"

Y-Axis Label = "Y-Axis"

Z-Axis Label = "Z-Axis"

Rotation About Z-Axis = 225

Tilt After Rotation = 30

Z-Axis Digits Displayed = 3

Z-Axis Scale Factor ~ Auto

Z-Tic Spacing = AUTO

Is This Correct (Y/n)

Input Date of Actual Run (default: 5-18-89 ) ?

Amplifier Gain Setting (default: 10 ) ?

Input Laser Identifier (default: HeNe ) ?

Input Detector Identifier (default: 4-8 ) ?

Input Pinhole Identifier (default: none ) ?

Run Date: 5-18-89

Gain: 10

Laser: HeNe

Detector: 4-8

Pinhole: none

33
Input Number of Desired Option? 10

Enhance the Contour Resolution Of Which Surface?

1 . Upper Surface

2. Lower Surface

3. Use Linear Contour Spacing

Input Number of Desired Option (default = linear): ?

Enter Contour Interval Step Size (as a Percentage of Full Scale)

(default = 20 % ) ? 5

Enter Labeled Contour Line Frequency (default = 2 ) ?

Choose Labeled Contour Line Type

1. Normal

2. Bold

3. Dashed

Enter Number of Desired Option (default = 1 ) ? 2

Do You Want Grid Lines (Yes or No, default = No ) ? yes

Linear Contour Line Spacing of 10 %

Labeled Contour Line Frequency of 2

Labeled Contour Line type: Bold

Plot Grid Lines? Yes

Is This Correct? (Y/n)

34
Do You Want To View or Plot the Surface?

1. View Surface

2. Plot Surface

3. Return to Main Menu

Input Number of Desired Option? 1

Do You Want To View or Plot the Surface?

1. View Surface

2. Plot Surface

3. Return to Main Menu

Input Number of Desired Option? 2

WORKING. .

Plotting grid

PLOT Version 3.11

(C) Copyright Golden Software 1987

Press Ctrl-C to abort...

Do you wish to shift the entire plot? No

Do you wish to scale the entire plot? No

Optimizing SURFDATA.PLT for printer output... Please wait

Processing record number 6940

SURFDATA.OPT has been created

Position paper and press any key to plot SURFDATA.OPT...

Press any key to return to TOPO. .

35
Detector Measurement

o o O o o o O o

q o o o o o q o o o o O o

CM d 00 d d CM d o o o o o

O CM CM CM ^

\

x

v

od d d CM do

o O O O o CO o o o o o O o

q o O q q o o o q q q q o

M" CM d oo d d CM d CO d d CM o

CM CM CM ^

T— T— -«

hc

D

cr

O)

00

00

LO

36
Input Number of Desired Option? 9

Presently: Min-X

Min-Y

Min-Z

0 Max-X = 24

0 Max-Y = 24

1573.761 Max~Z = -35.26251

1. Change Parameters

2. View Surface

3. Plot Surface

4. Raise Baseline

5. Offset Data so that Lowest Point = 0

6. Invert Data

7. Calculate Mean and Deviation of Z~Data over Present Area

8. Convert Data to Percentage of Full Scale

9. Restore Original Data

10. Topographical Maps

11. Change Output Device

12. Enlarge Portion of Graph

13. Print Run Information

20. Exit

Input Number of Desired Option? 6

Presently: Min-X ~ 0 Max-X = 24

1. Change Parameters

2. View Surface

3. Plot Surface

4. Raise Baseline

5. Offset Data so that Lowest Point = 0

6. Invert Data

7. Calculate Mean and Deviation of Z-Data over Present Area

8. Convert Data to Percentage of Full Scale

9. Restore Original Data

10. Topographical Maps

11. Change Output Device

12. Enlarge Portion of Graph

13. Print Run Information

20. Exit

Min-Y

Min-Z

0 Max-Y ~ 24

35.26251 Max-Z 1573. 761

37
Input Number of Desired Option? 12

Previously: Min~X = 0 Max~X ~ 24.

Values will be rounded to the nearest row of data

Input New Minimum X Value, 0 < ~ X < - 24

? 6

Input New Maximum X Value, 6 < X <~ 24

? 18

Presently: Min-Y = 0 Max-Y = 24

Values will be rounded to the nearest column of data

Input New Minimum Y Value, 0 < = Y <= 24

? 8

Input New Maximum Y Value, 8 < Y < = 24

? 18

New Values: liin—X - 6 Max — X ~ 18

Min-Y = 8 Max-Y ~ 18

Is This Correct? (Y/n)

38
Presently: Min-X

Min-Y

Min-Z

6 Max-X = 18

8 Max-Y « 18

35.26251 Max -Z 1573. 761

1

Change Parameters

2. View Surface

3. Plot Surface

4. Raise Baseline

5. Offset Data so that Lowest Point = 0

6

Invert Data

7. Calculate Mean and Deviation of Z- Data over Present Area

8. Convert Data to Percentage of Full Scale

9. Restore Original Data

10. Topographical Maps

1 1Change Output Device

12. Enlarge Portion of Graph

13. Print Run Information

20. Exit

Input Number of Desired Option? 7

Title: "5-23-89 Run 2

Listing Produced: 05-23-1989 12:55:58

For the Z Data in the Area Enclosed By:

Min-X = 6 Max-X = 18

Min-Y = 8 Max-Y = 18

MEAN

MAXIMUM

MINIMUM

MAX - MIN = VARIANCE ~

1556. 126503496504

1562. 303

1538. 233

24. 07000000000016

13. 64693313110668

Printing. .

Do You Want to Print the Run Inf.ormation? (y/N)

39
Presently: Min~X - 6 Max-X = 18

Min-Y = 8 Max-Y = 18

Mi n~Z ~ 35 . 26251 Max~Z - 1573-761

1 . Change Parameters

2. View Surface

3. Plot Surface

4-

Raise Baseline

5. Offset Data so that Lowest Point = 0

6 - Invert Data

7- Calculate Mean and Deviation of Z-Data over Present Area

8. Convert Data to Percentage of Full Scale

9. Restore Original Data

10. Topographical Maps

11- Change Output Device

12- Enlarge Portion of Graph

13. Print Run Information

20. Exit

Input Number of Desired Option? 13

Prepare Printer for Output and Press a Key

Or Enter an ’A’ to Abort:

T i tie: 5-18-89 Run 7"

Listing Produced: 06-02-1989 11 : 33 : 29

Actual Run Date:

Rotation (degrees)

Z-axis Tilt (degrees):

Amplifier Gain:

Laser Identifier:

Detector Identifier:

Pinhole Identifier:

Total Sample Points:

No optical fiber used

Mon i t or gain 10(2)

Tektronix 600 ohm load used

Detector 9 mm away from the objective

Daughter board gain setting 0

500 um/div

Max = 1574

Min - 35

5-18-89

225

30

10

HeNe

4-8

none

50 x 50

40
Presently: Min-X 0 Max-X

0 Max-Y

0 Max-Z

24

24

100

Min-Y

Min-Z

1. Change Parameters

2. View Surface

3. Plot Surface

4. Raise Baseline

5. Offset Data so that Lowest Point - 0

6. Invert Data

7. Calculate Mean and Deviation of Z-Data over Present Area

8. Convert Data to Percentage of Full Scale

9. Restore Original Data

10. Topographical Maps

11. Change Output Device

12. Enlarge Portion of Graph

13. Print Run Information

20. Exit

Input Number of Desired Option? 20

C : \SOURCE>rem Deleting Temporary Data Files...

C : \SOURCE>del dump2.grd

C:\SOURCE>del dump3.grd

C:\$OURCE>del surf*.CMD

C : \SOURCE>rem finished

C : \SOURCE >bye

This utility will park the heads on your hard disk

Strike any key to park the heads. . . . Control-Break

if you wish to abort.

Strike a key when ready . . Shutdown Utility Version 2.1 1/10/85

Shutdown cylinder - 614

Shutdown Completed -- OK to Turn Power OFF

41
Appendix G: Examples of graphics

Beam and detector graphics data at 9 mm, 15.2 mm, and 25 mm from a microscope

objective (xlO) with a 9 mm working distance. Beam radii, R, were approximately

70, 400, and 1100 pm, respectively. These data demonstrate system capability

and do not include system uncertainties. Distance between divisions was 250 pm.

Ten data points were averaged at each XYZ position plotted.

Detector graphics smooths and rounds with increasing beam radius. Raising the

baseline from 0 to 50 percent enhances the relief of the response.

42
Beam measurement at 9 mm from a microscope objective (xlO)

Title: 5-12-89 Run 3

Listing Produced: 05-18-1989 09:02:27

Actual Run Date:

Rotation (degrees)

Z-axis Tilt (degrees):

5-12-89

Detector Identifier:

Pinhole Identifier:

Total Sample Points:

Amplifier Gain:

Laser Identifier:

225

30

10

HeNe

SDC

10 urn 25 x 25

No optical fiber used

Monitor gain 10(2)

Tektronix 600 ohm load used

Detector 9 mm away from the objective

Gain setting 0

10 um/div

Max = 1304 Min = 14

43
Beam measurement at 9 mm from a microscope objective (xlO)

001 06 00 0Z 09 00 0tr 00 00 01 0

xy-z

44

5-

1

2-

89

Run
Beam measurement at 9 mm from a microscope objective (xlO)

<S

s) xy ~i

45

-12-89

Run
Beam measurement at 9 mm from a microscope objective (xlO)

46

5-12-89

Run
4.00

6.00

8.00

10.00

12.00

14.00

16.00

18.00

20.00

Beam measurement at 9 mm from a microscope objective (xlO)

Lf

47

19—

RQ

Run
Detector measurement at 9 mm from a microscope objective (xlO)

Title: "6-1-89 Run 4"

Listing Produced: 06-01-1989 14:49:09

Actual Run Date:

Rotation (degrees):

2-axis Tilt (degrees):

Amplifier Gain:

Laser Identifier:

Detector Identifier:

Pinhole Identifier:

Total Sample Points:

No optical fiber used

Monitor gain 10(2)

Tektronix 600 ohm load used

Detector 9 mm away from the objective

Daughter board gain setting 0

250 um/div

Max ~ 1598 Min = 19

6-1-89

225

30

10

HeNe

4-8

10 urn 50 x 50

48
Detector measurement at 9 mm from a microscope objective (xlO)

sv XV~Z

49

-

89

Run
Detector measurement at 9 mm from a microscope objective ( x 10) (Z axis baseline raised to 50%)

-89

Ru
0.00

4.00

8.00

12.00

16.00

20.00

24.00

28.00

32.00

36.00

40.00

44.00

48.00

Detector measurement at 9 mm from a microscope objective (xlO)

o o O O o o o o o

o o o o o o o o o o o o

4 d CD cm 00 4 d CD CM o o o

4- rO rO CM CM CM T- oo 4 o

o O O O o o o o o o o o o

o o o o o o o o o o o q o

00 4 o CD CM 00 *4 o CD CM 00 4 o

ro n CM CM CM T— 1—

51

0.00

4.00

8.00

12.00

16.00

20.00

24.00

28.00

32.00

36.00

40.00

44.00

48.00
Detector measurement at 9 mm from a microscope objective (xlO)

Title: "6~1~89 Run 4"

Listing Produced: 06-01-1989 15:41:50

For the Z Data in the Area Enclosed By:

Min~X - 16

Min-Y = 12

Max-X - 36

Max~Y “ 40

MEAN

MAXIMUM

MINIMUM

MAX - MIN = VARIANCE =

97. 80022295793076

99. 59788842697016

92. 16838308509782

7. 429505341872343

. 1954804760265207
Beam measurement at 15.2 mm from a microscope objective (xlO)

Title: 5-15-89 Run 1

Listing Produced

05-18-1989 09:06: 27

Actual Run Date:

Rotation (degrees)

Z-axis Tilt (degrees):

5-15-89

Detector Identifier:

Pinhole Identifier:

Total Sample Points:

Amplifier Sain:

Laser Identifier:

225

30

10

HeNe

SDC1

50 urn 25 x 25

No optical fiber used

Monitor gain 10(2)

Tektronix 600 ohm load used

Gain setting 0

Detector 15.2 mm away from the objective

50 um/div

Max * 503 Min = 6

53
Beam measurement at 15.2 mm from a microscope objective (xlO)

001 06 08 0Z 09 08 0tr 08 0£ 01 0

3 } x\/~Z

54

5-

1

5-

89

Run
Beam measurement at 15.2 mm from a microscope objective (xlO)

d

<so

<S»

<5> GO

<S> ®

® *

(M

<

"" X

<3

<s

no

d

c\j

<3—

CM

55

S-1S-R9

R,,n
Beam measurement at 15.2 mm from a microscope objective (xlO)

<S>

si xy-z

56

5-

1

5-

89

Run
4.00

6.00

8.00

10.00

12.00

14.00

16.00

18.00

20.00

22.00

Beam measurement at 15.2 mm from a microscope objective (xlO)

57
Detector measurement at 15.2 mm from a microscope objective (xlO)

Title

6-2-89 Run 1

Listing Produced: 06-02-1989 08:56:33

Actual Run Date: 6-2-89

Rotation (degrees):

Z-axis Tilt (degrees)

Amplifier Gain:

225

30

10

HeNe

4-8

Laser Identifier:

Detector Identifier:

Pinhole Identifier:

Total Sample Points:

none

50 x 50

No optical fiber used

Monitor gain 10(2)

Tektronix 600 ohm load used

Detector 15.2 mm away from the objective

Daughter board gain setting 0

250 um/div

Max = 1591 Min = 32

58
Detector measurement at 15.2 mm from a microscope objective (xlO)

59

-89

R,
Detector measurement at 15.2 mm from a microscope objective (xl )

(Z axis baseline raised to 50%)

: o

f o

; (0

1 *

C

c

\

s? xy-z

60

6-

2-

89

Run
CLOU

4.00

00

Detector measurement at 15.2 mm from a microscope objective (xlO)

c

riE

a

cc

I Cv

I cc

61
Detector measurement at 15.2 mm from a microscope objective (xlO)

Title: " 6-2--89 Run 1"

List i ng Produced: 06- 02-1989 09:20 : 12

For the Z Data in the Area Enclosed By : Min-X = 1

6

Max-X - 32

Min-Y - 16 Max~Y ~ 40

MEAN - 1566. 174807058824

MAXIMUM — 1584. 518

MINIMUM ~ 1544 . 179

MAX - MIN = 40. 33899999999994

VARIANCE ss 54. 65133210395016

62
Beam measurement at 25 mm from a microscope objective (xlO)

Title: 5-17-89 Run 3

Listing Produced: 05-17-1989 15:11:28

Actual Run Date:

Rotation (degrees):

Z-axis Tilt (degrees):

Amplifier Gain:

Laser Identifier:

Detector Identifier:

Pinhole Identifier:

Total Sample Points:

5-17-

225

30

89

10 £

HeNe

SDC1

100 urn 25 x 25

No optical fiber used

Monitor gain 10(2)

Tektronix 600 ohm load used

Detector 25 mm away from the objective

Gain setting 0

150 um/div

Max = 611 Min = .6

63
Beam measurement at 25 mm from a microscope objective (xlO)

001 06 0& 0Z 09 0S 0tr 0£ 0t 0

3? xv~z

64

5-

1

7-

89

Run
Beam measurement at 25 mm from a microscope objective (xlO)

©

©

©©

©©

00

© ®

® 3

CM

< ^ X

©

©

©

©

(M

©

CM

n

65

5-

1

7-

89

Run
Beam measurement at 25 mm from a microscope objective (xlO)

si xy-Z

G>

G>

<S>

<S> <S>

M-

<S> GO

<S> •

>-

<S> >o n


 CN)


 G>

M"

CM

66

5-17-89

Run
4.00

6.00

8.00

10.00

12.00

14.00

16.00

18.00

20.00

22.00

Beam measurement at 25 mm from a microscope objective (xlO)

67

17-flQ

Pun
Detector measurement at 25 mm from a microscope objective (xlO)

Title: 6-2-89 Run 2"

Listing Produced: 06-02-1989 10:44:14

Actual Run Date:

Rotation (degrees):

Z-axis Tilt (degrees):

6-2-89

Detector Identifier:

Pinhole Identifier:

Total Sample Points:

Amplifier Gain:

Laser Identifier:

225

30

10

M eN e

4 — 8

none

50 x 50

No optical fiber used

Monitor gain 10(2)

Tektronix 600 ohm load used

Detector 25 mm away from the objective

Daughter board gain setting 0

250 um/div

Max = 1591 Min = 35

68
Detector measurement at 25 mm from a microscope objective (xlO)

69

6-

2-

89

Run
Detector measurement at 25 mm from a microscope objective (xlO;

( Z axis baseline raised to 50%)

70

6-

2-

89

Run
Detector measurement at 25 mm from a microscope objective (xlO)

o o o o o o o O O o o o o

o o o o o o o o o o o o o o

b n- T— od in CN cn ID rn 6 b N o

fO m m CN CN CN CN T— T— 00

o O O O o o o o o o O o o o

o o o o o o o o o o O o o o

K N" 00 in CNj b cb in o K q od

N" m m m CN CN CN CN T— T— T—

71
Detector measurement at 25 mm from a microscope objective (xlO)

Title: " 6-2-89 Run 2"

Listing Produced: 06-02-1989 11:26:32

For the Z Data in the Area Enclosed By:

Min-X - 12

Min-Y - 16

Max-X = 28

Max-Y = 36

MEAN

MAXIMUM

MINIMUM

MAX - MIN = VARIANCE

1559. 379941176472

1568. 421

1546.008

22. 41300000000001

16. 15271968001316

72
Examples of measurements of detectors, Pin 4-7 and Pin 4-8, with 0 percent and

50 percent baseline are on pages 74-77.

73
Detector measurement, PIN 4-7. Baseline 0%

74

0921

8S01
Detector measurement, PIN 4-7. Baseline 50%

XV~Z

75

09218801
Detector measurement, PIN 4-8. Baseline 0 %

sj *\/~z

76

09238801
Detector measurement, PIN 4-8. Baseline 50%

/ / / / / /

• /

/

/

) i / / / / / /

i i / / / n~r/ /

/ / i~rrrrj^ ^

IZ6 '88 L86 ’8Z 066 '89 000 m0&

s ? x\/-Z

77

09238801
Appendix H: Graphics interface program

A commercial graphics program is used to generate high-quality three-dimensional

surface plots and topographical maps. An interface program is used to aid in

running the graphics program, and to provide additional data processing options.

For convenience, Golden Software Incorporated's Surfer program is used to

generate the graphics, and Microsoft Corporation's QuickBASIC and DOS Batch

processing are used in the interface program. Other software packages may work

equally well. The interface program requires the Batch programs SURF2.BAT and

INSTALL. Bat, and the two BASIC programs SURF1 . BAS and SURF2B.BAS. It has been

tested with DOS versions 3.2 and 3.3, Surfer versions 3.11 and 4.08, and QuickBASIC versions 4.0 and 4.5. This report describes how the program works, the

options it provides, and how the program is used.

SURF1 converts the original three-column data, generated with other programs,

into a double precision version of the grid format used by the graphics program.

The original data is a three -column ASCII file with the default file name DUMP.

It consists of rows containing the X and Y-position of the beam, and a Z-value

representing the detector's response at that position, separated by spaces. It

is assumed that this data set is square so that there are as many X-values as

Y-values, and that all points are present and equally spaced. The order in which

the data are listed is arbitrary. SURF1 sorts this data, determines the maximum

and minimum X, Y, and Z values, and then writes the files DUMP . GRD and

SURFAUTO . HST . DUMP. GRD contains the three -column data converted to double

precision grid format. The grid format used consists of lines of text. The

first lines contain information describing the data set, such as the dimensions,

maximum and minimum values. The remaining lines each contain a row of Z-values,

separated by spaces. The numbers are printed as double precision constants,

which preserves their precision. The original coordinates of each Z-value can

be computed from the descriptive information at the start of the file. Grid

format files are much smaller than the three column format files, yet contain

the same information. The string "NO" is written to the file SURFAUTO . HST , which

is used by SURRF2B along with DUMP. GRD.

78
SURF2B calls the graphics program so that the operator does not have to be

trained in its use. It also provides additional data processing options. SURF2B

is a complicated program which is called by the program SURF2.BAT. This is

% necessary because of the way the graphics program is called. Graphics requires

almost all the memory available to produce graphs of 100 x 100 points. Hence,

SURF2B cannot call the graphics program in a BASIC command shell, or there will

be insufficient memory left for this size of graph. The file SURF2 calls SURF2B,

and then jumps to the file SURF4.BAT. SURF4 is created by SURF2B. Depending

on the option selected in SURF2B, SURF4 either calls the graphics program and

jumps to SURF2 , or terminates. This process reduces the memory as seen by the

graphics program by only about 2 kbytes, which allows the graphics program to

produce the desired graphs if a sufficiently "clean boot" is used. A clean boot

loads no or very few memory resident programs so that the maximum amount of

memory is available. SURF2B and the graphics program are called from the Batch

programs with a new DOS command processor so that control is returned to the

Batch file afterwards. For example. SURF2B is called with the command: "COMMAND

/C SURF2B.EXE". If DOS version 3.3 or above is used, the faster command "CALL"

can be used in place of "COMMAND /C" . If SURF2B is terminated abnormally by an

error or power failure, these processes can become confused and SURF2B will no

longer run. This problem can be corrected by running SURF1 again.

Because SURF2B ends when the graphics package is called, the program's

environment must be saved to disk before the call, and restored afterwards. This

is done by writing all information that must be retained, such as axis labels,

to the history file SURFAUTO . HST . When SURF2B begins, it first checks to see

if the first line of the history file contains the string "NO". If it does, no

history exists so the user is prompted for label information, Z- scale factor,

view angle, and other options. Otherwise, this information is read from the

history file.

Once the history information is entered, the operator is presented with the main

menu. Options on the main menu are described below.

79
1 . Change Parameters:

Allows the operator to change the history parameters entered when the program

was first run. These parameters consist of: graphics package options

including Plot Title, X-Axis Label, Y-Axis Label, Z-Axis Label, Rotation

About Z-Axis, Tilt After Rotation, Z-Axis Digits Displayed, Z-Axis Scale

Factor, and Z-Tic Spacing; and run information including Run Date, Amplifier

Gain, and identifiers for the Laser, Detector and Pinhole used.

2. View Surface:

Instructs the graphics program to produce a surface plot of the presently

active region, and to send the output to the screen. The active region of

the data is defined in Enlarge Portion of Graph below.

3. Plot Surface:

Instructs the graphics program to produce a surface plot of the presently

active region, and to send the out put to the hard copy device.

4. Raise Baseline:

Prompts for a minimum Z-value, and raises all points below the new minimum

to the new minimum Z-value.

5. Offset Data so that Lowest Point = 0:

Adds an offset to all Z-values, so that the minimum Z-value is at 0.

6. Invert Data:

Changes the sign of all Z-values.

7. Calculates Mean and Deviation of Z-Data over Present Area:

Calculates the mean and variance (sigma squared) of the Z-values in the

presently active region, and displays the results on the screen with a hard

copy option. Title, date of printing, coordinates of the active region

used, maximum- Z, minimum- Z, and Z- spread are listed along with the mean and

variance. If the hard copy option is chosen, the Print Run Information

option is presented.

80
8. Convert Data to Percentage of Full Scale:

Linearly scales all Z-values so that the minimum Z-value is at 0, and the

maximum Z-value is at 100.

9. Restore Original Data:

Restores the original data set created by SURF1 , without modification.

10. Topographical Maps:

Prompts for information concerning the topographical map, and produces the

map as described in the next section.

11. Change Output Device:

Calls the graphics program's installation program so that the hard copy

output device can be changed. The installation program is called through

the STALL.BAT program.

12. Enlarge Portion of Graph:

Prompts for a rectangular area within the data set. This area will become

the active region for plotting and some data analysis options.

13. Print Run Information:

Produces a hard copy listing including: the title; listing date and time;

run date; Z-axis rotation and tilt; amplifier gain; laser, detector and

pinhole identifiers; and the dimensions of the data set.

20. Exit:

Terminates the SURF2 program.

Additional information is requested when the Topographical Map option is

selected. This information is used by the graphics package's topographical map

program. These prompts are described below, in the order in which they will

appear

81
Enhance the Contour Resolution:

The upper or lower portion of the active region of the surface can be

enhanced, or a linear contour spacing can be used. Enhancement of the

surface is provided by plotting more contour lines in the area to be enhanced

than over the rest of the surface. When enhancement is chosen, the operator

is prompted for the amount of the surface to enhance, the contour spacing

in the enhanced region, and the contour spacing outside of the enhanced

region. If linear contour spacing is chosen, the operator is prompted for

a single contour spacing used over the entire surface. All spacings are

expressed as a percentage of full scale.

Labeled Contour Line Frequency:

Not all contour lines are labeled with their Z-values. This parameter

determines the frequency of the labeled contours. For example, entering a

0 results in no labels, 1 results in every contour line being labeled, and

2 results in every other contour line being labeled.

Labeled Contour Line Type:

Labeled contour lines can be drawn differently from unlabeled contour lines,

to aid in reading the map. Normal, bold and dashed labeled contour lines

are supported.

Grid Lines

Rectangular grid lines are enabled or disabled at this prompt. If enabled,

dashed grid lines are printed for each labeled tick on the axes. Labeled

tick spacing is determined adequately by the graphics program, so no manual

override is provided.

View of Plot the Surface:

This prompt provides the option of sending the map to the screen or hard

copy device, or aborting the plot and returning to the main menu. If the

map is generated, the graphics program is called at this point.

For ease of use, all options furnish reasonable default values. To perfom some

functions, SURF2B may create the temporary double precision data files DUMP2.GRD

82
and DUMP3.GRD, but the DUMP . GRD file containing the original data is preserved.

To reduce accumulated roundoff error, all data processing is done in double

precision arithmetic, and intermediate results are stored as ascii double

precision numbers. However, since BASIC insists on writing a "D" instead of an

"E" to designate the exponent when double precision numbers are printed, the grid

file is converted to single precision before it is sent to the graphics package.

The temporary single precision grid file created is called SURFDATA . GRD

Temporary files are deleted when SURF2 exists.

The additional prompts when producing topographical maps were found to be

necessary for production of a useful map. When the topographical map option is

selected, the operator is first prompted for which part of the surface, if any,

to enhance. The detector data has a characteristic shape resembling the top hat

function, there is a raised portion corresponding to when the beam strikes the

detector, surrounded by a skirt or steep drop-off to the background level. The

background level corresponds to the detector not illuminated. The region of

interest is usually the portion of the data corresponding to where the beam

strikes the active portion of the detector, and the details of this region are

dwarfed by the magnitude of the change to the background level. The contour

lines shown on topographical maps are usually equally spaced. But for this

surface, equal spacing will result in loosing all detail in the active region

or having a great many lines in the skirt. So an option is provided which allows

enhancement of either the top or bottom of the surface, by using a finer contour

level spacing there than over the rest of the surface. For example, the default

uses a spacing of 0.5% over the top 5% of the Z-data range, and a spacing of 20%

over the rest of the range. This results in a pleasing map of the entire data

set. This contour level information is written to the file SURFLVL.DAT, which

is used by the graphics program.

Alternately, the enlarged portion of the graph option can be used to limit the

active region to the active detector area. Then linear contour spacing is

adequate, but some features near the skirt are cut out. Also, the raise baseline

option can be used to enhance the upper portion of the surface by decreasing the

height of the skirt. This option may however cut off the bottom of holes in the

active area, making them appear less deep than they actually are. These two

83
techniques can be applied to the surface plots as well as topographical maps.

With surface plots, the features may become so pronounced that the Z-scale

factor, a history parameter, must be reduced for the surface plot to be

understandable

For example, if the raise baseline technique is used with a surface plot, the

suggested procedure is to invert the data if necessary so that the surface of

interest is on the top. Then, convert the data to a percentage of full scale,

and the raise the baseline to as high a percentage as possible without cutting

off the data of interest (typically 95%) . It may then be necessary to reduce

the Z-scale factor if the features are too pronounced.

The options selected by the user, and the data file names are passed to the

graphics program via the command files SURFAUTO.CMD and SURFTOPO.CMD. The

graphics program used can take instructions from these command files as if they

were entered interactively. It should be noted that the surface plot shows the

real data points connected with lines, no interpolation or curve fitting is

done. Smoothing is available in the graphics package, but is not used because

of its distorting effect and memory requirements. The topographical map however

is interpolated from the data. Thus, when the contour level spacing is changed,

some features may also change slightly.

The interface program provides an easy to use set of commands for generation of

high quality surface plots and topographical maps. The complete program source

code consists of the files: SURF1.BAS, SURF2.BAT, INSTALL. BAT and SURF2B . BAS

The file SURF4.BAT will be created by SURF2B, and other temporary files are

created and deleted. The compiled BASIC programs, the programs, and the threecolumn data file must be in the default directory when the program is run. The

graphics package, BASIC's support file BRUN4x.EXE, and DOS's COMMAND.COM must

be accessible through the DOS PATH.

84
Appendix I: Placing the unknown detector in the (m=0) or (m=2) beams of the beam

splitter wedge

The unknown detector is attached to XY linear translation tables.

By rotating the latter to another set of holes in the steel table supporting

them, the detector is placed either in the (m=0) beam or the (m=2) beam of the

beam splitter wedge at 0.6328 /zm.

The position of the detector will differ by small angles at other wavelengths.

The deviation angles of the (m=0) and (m=2) beams from the beam entering the beam

splitter are 1.60° and 8.79°, respectively.
Appendix J: Linear detector for the visible and near infrared laser wavelengths

1 . Discussion

A.L. Rasmussen

NIST calibrates laser power and energy measuring detectors that are used

as transfer standards. To calibrate transfer standards reliably requires

determining their linearity as well as uniformity of responsivity . In order

to improve device evaluation, NIST has developed systems to measure these

parameters. The purpose of this discussion is to describe the design,

calibration, and application of a linear detector of laser power. A system

uses this detector to assure operation below saturation. It measures

uniformity of detector responsivity and beam dimensions and is described in

the main report.

The linear detector of laser power was calibrated with a cw laser at

0.6328 pm in the C series system, the national standard for laser power and

energy for visible and near infrared wavelengths [1]. It was called Rosy 7-1

because of the rosy glow of the laser beam emitted from the integrating sphere

in front of the detector. Because it is linear at 0.6328 pm, Rosy 7-1 is

is assumed to be linear at each operating wavelength from 0.4 to 1.1 pm

provided it is not used near saturation. NIST transfer standards made from

detectors similar to Rosy 7-1 are linear at 1.064 pm [2],

2Description

Rosy 7-1 is a temperature-controlled silicon PIN photodiode with -180 V bias

and an integrating sphere mounted in front of it. The integrating sphere

transforms any beam into a highly uniform beam entering a specific area

of the detector [3]. A nanovolt amplifier following the detector delivers

-10 V to the readout, either an A/D card or a digital voltmeter attached to a computer. The alignment parts, mirror and iris attached to sphere entrance,

and positioner with six degrees of freedom greatly assist in aligning the

integrating sphere in the beam. The mirror reflects the beam on itself and

the iris helps center the beam. See figures 1 and 2 and the key to figure 1.

86
3 . Calibration

Rosy 7-1 was calibrated with a cw laser at 0.6328 /im in the C series system,

which is traceable to SI standards of voltage and current. The power in Rosy

7-1 is determined from the product of the beam splitter ratio and the power in

the C series calorimetric standard.

The output of Rosy 7-1 enters a nanovolt amplifier with 0.01% uncertainty of

the gain. The amplifier is connected to either an A/D card or a precise digital

voltmeter attached to a computer.

Calibration and statistical data of Rosy 7-1 are given in tables 1 and 2. The

area of the beam is approximately equal to the area of an iris , located

o immediately in front of the detector and opened to the 1/e radius of the beam

as determined by power measurements.

Table 1 gives responsivity values in order of ascending power. Two beam

splitters and loads had to be used to cover the range. Calibration was from

5»10” 7 to 1.5»10”2 W and about 2.5«10” 5 to 8»10-1 W/cm2

. The results had 0.2

percent uncertainty of linearity and 0.6 percent uncertainty of calibration.

The linearity of Rosy 7-1 should prevail at each operating wavelength

throughout its range as long as it is not saturated. Rosy 7-1 may be

used at other wavelengths as a linear detector of laser power.

4 . Application

Rosy 7-1 monitors laser output in a system that determines uniformity of detector

responsivity and measures beam dimensions. An unknown detector, or pinhole and

detector, is scanned in the beam of the system. See Fig. 3. Using the monitor

also reduces the effect of laser fluctuations on measurements.

87
Appendix J References

J [1] Case, W.E. Documentation of the NBS C, K, and Q laser calibration

systems. Nat. Bur. Stand. (U.S.) NBSIR 82-1676; 1982 September.

J [2] Rasmussen, A.L.; Sanders, A. A. Transfer standards for energy and

peak power of low-level 1.064 micrometer laser pulses and continuous

wave laser power. Opt. Eng. 25(2): 277; 1986 February.

J [3] Eckerle, K.L.; Venable, W.H., Jr.; Weidner, V.R. Averaging sphere

for ultraviolet, visible, and near- infrared wavelengths: A highly

effective design. Appl. Opt. 15(3): 703; 1976 March.

88
Table 1. Rosy 7-1 Linear Detector Calibration Data taken

August 1988 at 0.6328 HeNe Laser Wavelength

Run Responsivity Input power Output Load* BS

Number (V/W) (W) (V) (O) Ratio*'

8 -34.84 5.025-10'7 -1.751-10'5 1000 819.3

5 -34.76 1.213-10-6 -4.216-10'5 ft ft

4 -34.63 2 . 047 • 10" 6 -7.090-10"5 ft tt

9 -34.58 3 . 606 • 10‘ 6

- 1 . 247 ' 10~ 4 ft tt

2 -34.74 6 . 382 • 10~6 -2.217' 10” 4 ft tf

7 -34.67 8.663-10'6 -3.004-10'4 ft ft

3 -34.68 1.071-10"5 -3.714-10'4 ff ft

1 -34.73 1.591-10'5 -5.527-10"4 ft ft

6 -34.72 1.943-10' 5 -6.747-10-4 ft tt

17 -34.72 3.081-10-5 -1.070-10'3 ft 11.53

18 -34.56 6.410-10" 5 -2.215-10-3 tf tt

10 -34.57 1 . 502'10~ 4 -5.191-10'3 ft tf

15 -34.55 1.66610'4 -5.758-10"3 ft tf

11 -34.64 1.689-10"4

- 5 . 849 ' 10” 3 tf tt

14 -34.55 4.741-10'4 -1.638 - 10’2 tf tt

13 -34.56 7.061-10-4 -2.425-10'2 tt tf

16 -34.55 9.719-10'4 -3.358 10-2 ff tt

12 -34.62 1.349-10"3 -4.670-10"2 tf ff

19 -34.62 1.460 10"3 -5.055-10"2 tt tf

25 -34.75 2.574-10"3 -8.942-10-2 tf ft

24 -3.469 2.577-10"3 -8.940-10-3 100 tt

26 -34.78 2.775 - 10”3

- 9 . 652 ' 10”2 1000 tf

23 -3.465 4.137-10'3 -1.433-10'2 100 tt

22 -3.467 8.091-10*3

- 2 . 805 • 10"2 tf tt

21 -3.473 1.164-10'2 -4.041-10-2 tt tf

20 -3.480 1.537 10"2 -5.348 10"2 ff tt

* 0.1% uncertainty

**BS ratio = beam splitter ratio in C series system

89
Table 2. Statistical Data of Rosy 7-1 Linear Detector Calibration data

in Table 1 at 0.6328 /j,m HeNe Laser Wavelength

Calibration

Average Responsivity SD % n Load Beam area (cm2

) (V/W) m (at 1/e2 points)

-34.66 0.26 21 1000 ~2 ’ 10”2

-3.471 0.17 5 100 -2-10'2

Power and Power Density Measurement Range

Minimum Maximum

Power (W) 510~7

Irradiance (W/cm2

) 2.5 10” 5

1.5-10'2

8

- 10 -1

C series

total

uncertainty

0.4%

0.4%

Calibration Uncertainty

Load Total

(ft) uncertainty

1000 0.60%

100 0.46%

Linearity

uncertainty

0.17%

0.23%

90
Key to Figure 1

1. Readout: A/D card or voltmeter attached to a computer.

2. Nanovolt amplifier: gains 102

, 10 3, 10 4 and 10 5

; 10 V maximum output.

3. Detector: silicon PIN photodiode (Rosy 7-1), ~1 cm2 area, 100 Q and

1000 Q load, 0.4 - 1.1 m wavelength range.

4. Integrating sphere: cube with 3.57 cm diameter sphere inside with white

coating of barium sulfate, 0.766 cm inside diameter entrance, ~ 0.8 cm

inside diameter exit, -0.2 throughput (decimal fraction of entrant

energy emerging from sphere), beam distributed uniformly on detector,

baffle inside sphere stops first reflection entering the detector.

5. Alignment parts: front surface mirror to reflect the beam on itself, iris

to center the beam into the detector.

6. Bias power supply: -180.0 V.

7. Temperature controller: maintain detector temperature about 30°C

+ 0 . 1°C with a readout of 3900 Q.

8. Temperature controller power supply: 15 V.

9. Positioner with six degrees of freedom: align detector.

91
BIAS

P.S. 5

>>» I§

ssa&

3kae3<

U3

toO •H

Ph

hz>OQ<

iy

QC

92
Figure 2a. Front view of the linearity transfer standard Rosy 7-1 shows a black cube containing the integrating sphere below the chassis

holding the detector, the temperature controller, and the

circuitry. Sphere entrance and positioning knobs below are also

shown. A mirror and an iris used to align the sphere are attached

to threads surrounding the sphere entrance.

93
Figure 2b. Rear view of the linearity transfer standard Rosy 7-1 in the

scanning system shows Daniel Habernall adjusting the position of

the standard. The beam splitter with dark frame and the scanner

with motor and cable visible are in the background.

94
Figure 3. Detector scanning system using linearity

transfer standard, ROSY 7-1.

95
JiST-1 14A

REV. 3-89)

U.S. DEPARTMENT OF COMMERCE

NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY

BIBLIOGRAPHIC DATASHEET

1. PUBLICATION OR REPORT NUMBER

NISTIR 90-3937

PERFORMING ORGANIZATION REPORT NUMBER

3. PUBLICATION DATE

April 1990

TITLE AND SUBTITLE

SCANNING SYSTEM FOR MEASURING UNIFORMITY OF LASER DETECTOR RESPONSE AND

LASER BEAM DIMENSIONS

AUTHOR(S)

A.L . Rasmussen, W:E. Case, and A. A. Sanders

PERFORMING ORGANIZATION (IF JOINT OR OTHER THAN NIST, SEE INSTRUCTIONS)

U.S. DEPARTMENT OF COMMERCE

NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY

qaithers««ro,-md- 20899 Boulder, Colorado 80303-3328

7. CONTRACT/GRANT NUMBER

8. TYPE OF REPORT AND PERIOD COVERED

SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (STREET, CITY, STATE, ZIP)

I. SUPPLEMENTARY NOTES

DOCUMENT DESCRIBES A COMPUTER PROGRAM; SF-185, FIPS SOFTWARE SUMMARY, IS ATTACHED.

ABSTRACT (A 200-WORD OR LESS FACTUAL SUMMARY OF MOST SIGNIFICANT INFORMATION. IF DOCUMENT INCLUDES A SIGNIFICANT BIBLIOGRAPHY OR

LITERATURE SURVEY, MENTION IT HERE.)

A computer - controlled scanning system constructed at NIST/Boulder moves a detector

or a pinhole attached to a detector in a plane perpendicular to the axis of a

stationary laser beam. A linear detector monitors the laser beam. The system

measures the uniformity of laser detector response and the laser beam dimensions.

The device to be measured is attached to computer controlled X-Y translation tables

that scan a maximum area of 15 cm x 15 cm with 10 -4 cm resolution along each axis

Detector and monitor outputs are digitized with a computer board. Output versus

position is represented in contour maps and surface graphics on the computer, the

plotter, or the printer. Choice of matrix dimensions and step sizes of the scanned

area determine the resolution of graphics. Maximum, minimum, average and variance

data of the Z output of a detector for a chosen X-Y area provide additional uniformity

information. High precision fiber couplers can be used to spatially filter and/or

collimate the beam. Available sources are conventional lasers from the visible and

the near infrared wavelengths or laser diodes at 0.82, 1.3 and 1.55 /um wavelengths.

A precision positioner along the optical axis moves the measurement device and

controls the size of the beam entering it. Beam dimensions and detector response

data are given. This report documents the use of the system to calibrate detectors.

>. KEY WORDS (6 TO 12 ENTRIES; ALPHABETICAL ORDER; CAPITALIZE ONLY PROPER NAMES; AND SEPARATE KEY WORDS BY SEMICOLONS)

beam dimensions; computer-controlled scanning system; detector and beam graphics;

detector and beam scanning; laser detector response; laser power monitor; linear

detector; uniformity

i. AVAILABILITY

UNLIMITED

FOR OFFICIAL DISTRIBUTION. DO NOT RELEASE TO NATIONAL TECHNICAL INFORMATION SERVICE (NTIS).

X

X

ORDER FROM SUPERINTENDENT OF DOCUMENTS, U.S. GOVERNMENT PRINTING OFFICE,

WASHINGTON, DC 20402. ORDER FROM NATIONAL TECHNICAL INFORMATION SERVICE (NTIS), SPRINGFIELD, VA 22161.

14. NUMBER OF PRINTED PAGES

100

15. PRICE

LECTRONIC FORM U.S. GOVERNMENT PRINTING OFFICE: 1990-0-775-299/25101