LASERM AT E R I A L SCORPORATIONInformation about our Nd:YAG laser crystal products• Laser Rod Specifications• Ordering Information

Information about Nd:YAG & crystal growth• Nd:YAG Production at LMC• Notes about Nd Concentration• Properties of Nd:YAG

For more information, visit our web site
http://www.LaserMaterials.com

Product Brochure
Neodymium YAG

Nd:YAG Production
Laser Materials Corporation produces Nd:YAG boules,
fabricated laser rods and slabs. Our crystal growthfacility in Vancouver, Washington exclusively produces
large diameter boules (currently, Ø82 mm) in lengths
up to 250 mm while retaining acceptable Neodymium
concentration levels. As a crystal grower, we concentrate on developing and improving the crystal growth
process to produce high yields and consistently highmaterial quality. Pure raw materials, precise formulation, and exacting growth control are the keystones ofour operations.

Ø75 x 208 mm boule section(Nd:YAG, 1.1 atom % Nd concentration)• Better than 99.997% pure yttrium and aluminum oxides, and 99.99%
pure neodymium oxide are used.
• 99.999% pure or better shield gases are used throughout the crystal
growth process.
• All raw materials are stored and prepared in a clean environment.
• Constituent powders are thoroughly dried in high temperature ovens toreduce hydroxyl impurities.
• The dried raw materials are carefully weighed on precision balances toinsure precise stoichiometry and dopant concentration.
• Computer control of the growth process and associated facilities produces the stable conditions required for consistent boule growth;cooling water and room air temperatures are maintained to withinclosely controlled tolerances.
• Crystal growth control is based on weight gain for the most consistentboule diameter possible.

Laser rod "blanks" are extracted from completed boules
using a diamond core drill; for slabs, a slicing saw is used to
cut out the rough rectangular shape. In either case, therough finished blanks are then sent out for the finishing
operations of precision grinding to final size, polishing, andanti-reflection coating. You have the option of purchasing
finished rods directly from us or purchasing unfinished"blanks" and using the fabricator of your choice.
core drilling a Ø5 mm rod from a
Ø75 x 208 mm boule section

Nd:YAG Crystal Growth
Growth of neodymium doped yttrium aluminum garnet (Nd:YAG) crystals by the Czochralski technique is the methodof choice for virtually all commercially available Nd:YAG. This is a time consuming process requiring careful
control of the growth environment over a period of 4 to 5 weeks just to produce one crystal boule. Still, theCzochralski method has proven to be the only acceptable way to produce Nd:YAG with sufficient optical clarity andhomogeneity for use in a laser system.
Crystal quality Vs. Boule size
One of the most important advances in Nd:YAG production in recent years has been the trend toward larger diameter boules.
Internal strain in the grown boule is the principle cause of optical distortion in finished laser rods more than a few tens ofmillimeters in length (in shorter rods, the quality of the end finish is more important). Larger boules have significantly lower
strain levels over much of their cross section resulting in significantly lower optical distortion in finished rods.
An additional advantage of larger boules is reduced cost. The cross-sectional area is increased while the linear growth rate
remains comparable, resulting in an increased rate of material growth. At large diameters, Nd:YAG is more sensitive to processparameter fluctuations and obtaining high yields of good product is more difficult. But as a result of improved control
electronics and computerization of the growth process, growth rate fluctuations can be maintained well within tolerance toprovide high yields of good product at large diameter.

Neodymium Concentration

For material less than 200 mm, the average concentration willvary depending on from where in the boule the material is cut.
Each individual laser rod we ship is supplied with data including
the average Nd concentration and the change in concentration
over the rod's length. Standard tolerances for various rod lengths
are listed on our laser rod specification sheet.
It should be noted that the absolute accuracy of the neodymium
concentration must take into how accurately the distribution
coefficient (ratio of dopant concentration in the crystal to that inthe melt) is known. At Laser Materials Corporation our formulations are based on a value of 0.18, which is consistent withindustry practice and most determinations in the literature.

2.50

2.00

1.50

1.00

0.50
00.2

0.4

0.6

0.8

fraction of melt pulled

1.30

1.20

[Nd] (atom %)At Laser Materials Corporation, we grow boules at two average Ndconcentrations: 0.80% Nd and 1.10% Nd. The Nd concentration
profile for each is illustrated in the lower graph. The composition is engineered to provide the specified average concentrationin 200 mm lengths. Lengths up to 250 mm can be provided withslightly higher average Nd concentrations.

[Nd] (atom %)In neodymium doped yttrium aluminum garnet, neodymium substitutes for yttrium in the crystal lattice. However, because
neodymium is larger than yttrium, this substitution does not occur readily. In fact, the concentration of neodymium in thecrystal is only a small fraction of its concentration in the melt. Since the growing crystal is continually rejecting neodymium,the concentration of the melt (and hence the crystal) increases as the growth progresses. To minimize this effect it is necessary
to use a large crucible and to pull only a small fraction (typically4.0020-30%) of the total material available. The upper graph shows
3.50
how the concentration of neodymium increases as a function of3.00
melt fraction pulled.

1.10

1.00

0.90

0.80

0.70
050

100150net boule length (mm)200250Nd:YAG Material Properties
Chemical/PhysicalLaser/Spectroscopic

Chemical Formula
Formula Weight
Crystal System/StructureSpace Group
Lattice Constant
Melting Point
Density
Hardness (Knoop)

Y 2.97Nd 0.03Al 5O 12595.3 g . mole -1Cubic/Garnet
10O h -Ia3d
12.01 Å1950 ±20 °C
4.55 g. cm -3
1350 ±35 kg . mm -2

Lasing System
Lasing Upper State
Fluorescent Lifetime
Main Pump Bands
4

Modulus of Elasticity (E)R2 → Y1
R1 → Y1
R2 → Y3
R1 → Y2
R1 → Y3
R1 → Y4
R2 → Y5
R2 → Y6
R1 → Y5
R1 → Y6

310 GPa(45 x 10 6 psi)
0.3
175-200 MPa(25-30 x 103 psi)

Poisson's Ratio (ν)
Tensile Strength (σ t )Thermal0.59 J . g -1 . K -1
0.13 W . cm -1. K -1
7 x 10-6 K -17-8 W. cm -1

Specific Heat Capacity (C p )Thermal Conductivity (k)Thermal Expansion Coef. (α)
Thermal Shock Parameter (R)From the Thermal Shock Parameter, the fracture limit for thermal dissipation in a CW laser rod can be calculated:
For rods it is independentof rod diameter (= 8πR)

175-200 W . cm -1

For slabs it is dependent on
the aspect ratio (= 12R. W/t).
For a 4:1 aspect ratio (=48R)

330-390 W . cm -1

Note: These values are absolute maxima and can begreatly affected by surface finish, fixturing, etc.

Optical1.818 at 1.064 µm
9.05 x 10 -6 K -1

Refractive Index (n)Temperature Coef. (dn/dT)
Wavelength Dependence:
0.80 µm0.90 µm
1.00 µm
1.10 µm
1.20 µm
Elastooptic Coefficients:
P 11
P 12
P 44

OR

© Copyright 1995--1999
electronic version

PO

R

TI

Relative Laser
Performance

1.05205
1.06152
1.064141.0646
1.07381.07801.1054
1.1121
1.11591.122674692
100 (Principle)
5065
34
949
4640

F 3/2 → 4I 13/2 Stark Level Transitions:
Transition

R2 → X1
R2 → X2
R1 → X1
R1 → X2
R2 → X3
R2 → X4
R1 → X4
R2 → X6
R1 → X7

Wavelength (µm)

Relative Laser
Performance

1.31881.32001.33381.33501.3382
1.34101.3564
1.41401.4440

34
9
13
15
24
9
14
1
0.2

Unless otherwise noted, data is for 1% Nd (atomic) at 300K. For
more information, consult the following references from which theabove data was compiled.

Alexander A. Kaminskii, Laser Crystals-Their Physics and Properties, Second Edition (Springer-Verlag, Berlin, Heidelberg, 1990)
CRC Handbook of Laser Science and Technology, Volume V,
Optical Materials, Part 3: Applications, Coatings, and Fabrication, Marvin J. Weber Ed. (CRC Press, Boca Raton, FL 1987)-0.0290.0091-0.0615

A4Wavelength (µm)

Walter Koechner, Solid-State Laser Engineering-Third Completely
Revised and Updated Edition (Springer-Verlag, Berlin, Heidelberg
1992)

1.82451.8222
1.81971.81701.8152LASER
MATERIALS
C

F 3/2 → 4I 11/2 Stark Level Transitions:Transition

MechanicalFour Level
4F 3/2230 µs0.75 & 0.81 µm

ON12706 NE 95th St., #102
Vancouver WA 98682U.S.A.
Tel.: (360) 254-4180
FAX: (360) 254-4182
web: www.LaserMaterials.com
e-mail: hq@LaserMaterials.com

Nd:YAG Laser Rods
0.10 ± 0.05 x 45°

serial number

D

1.6µm
0.8µm

+0.00
-0.03

5' A
5 ° <111> (Crystal)L

10/5 scratch/dig

+0.5
-0.5

0.1 λ @632.8nm

–A–

10" A

Revised specifications effective 30-April-2001

Standard GradeLDmm

mm505050
65
60
65
75
75
75
75
75
75
100
100
100
100
100
125
125
125
125
125
150
150
150
200
200
200
250
250
250

34534534566.35
84566.35
856
6.35
8
9.53
6.35
8
9.53
8
9.53
108
9.53
10Premium Grade

Standard [Nd]=1.1 Atom%

Low [Nd]=0.8 Atom%

Extinc. Ratio Wave. Error Extinc. Ratio Wave. Error Tolerance of ∆[Nd] Over Tolerance of ∆[Nd] Over(dB)>25>24>23>22>21>20>19>18(λ)<.19<.21<.24<.20<.22<.26<.21<.24
<.28
<.31
<.32<.38<.28<.32<.36<.37<.44<.36
<.41
<.43
<.51<.59<.48<.58<.67<.71<.82<.86<.84<.98<1.03(dB)>30>29>28>27>26>25>24>23(λ)<.13<.15<.16<.14<.15<.17<.15<.17<.18<.20<.21<.24<.18<.21<.23<.24<.28<.23<.26<.27<.31<.36<.30<.35<.40<.42<.49<.51<.50<.57<.60

Average [Nd] Rod Length Average [Nd] Rod Length

±.08

0.06

±.07

0.05

±.08

0.08±.07

0.06±.08

0.10±.07

0.07±.08

0.13±.06

0.09±.07

0.16±.05

0.11

±.05

0.18±.04

0.13±.02

0.23±.02

0.17±.03

0.31±.03

0.22Coatings
TypeAR @1064nm
HR @1064nmPartially Reflecting
Partially Reflecting
Partially Reflecting%R per Surface

Reflectivity

Damage Threshold(20nS Pulse, GW.cm-2)

Damage Threshold(CW, kW.cm-2)<0.15>99.9
95 to 99 ± 0.5
90 to 95 ± 1
10 to 90 ± 3>1.4>1.0>1.0>1.0>1.0>25>25>25>25>25

Ordering Information

Radiused End
R–A–5'AR (m)0.5± .05
1.0± .1
2.0± .2
3.0± .3
5.0± .5
10± 1

Wedged EndA
30' ± 10'1° ± 10'2° ± 10'6° ± 10'8° ± 10'
Note: if both ends wedged parallel,
A-B angle < 10"A
Incident Beam

61° 12' (Brewster's Angle)

Brewster End% Reflectivity = .06% for plane
polarized incident beam at limitof angle tolerance.

28° 48' ±30'Part Numbering[Atom % Nd]NY[P] – [Diameter (mm)] – [Length (mm)] – [A-End/B-End] – [A-Coating/B-Coating]
0.80% --- 08
1.10% --- 11

Premium --- P
Standard --- Blank

Note:

Flat -------- F
Radiused -- R+Radius
Indicateanti-parallel
Wedged --- W+Angle
wedged ends by a negative
Brewster -- Bangle on one end
Special ---- SUnfinished N

Anti Reflection ------ A
High Reflection ------ H
Partial Reflection ---- P(%R)
None ------------------- N

Example:08NY-6.35-100-W1/W1-A/A
Designates 0.08% standard grade Nd:YAG , D=6.35mm L=100 mm, both ends angled 1° parallel, and an AR coating on
both ends.

To request a quote, you can call or FAX us with your requirements at the numbers below. Or, click this
hyperlink to go to an online quote request form at the Laser Materials Corporation web site.

LASER
MATERIALS
COR© Copyright 1993-2001
electronic version

PO

RA

TION

12706 NE 95th St., #102
Vancouver WA 98682
U.S.A.
Tel.: (360) 254-4180
FAX: (360) 254-4182
web: www.LaserMaterials.com
e-mail: sales@LaserMaterials.com