Lion (Motor)
Tunable External Cavity Diode Laser
Littman/Metcalf Configuration
Automated Wavelength Scans

Scientific Lasers

TEC 500 & TEC 520 Motorized

Vorsprung durch Innovation

How does our Laser
tune modehop-free ?
Physical Basics

Pivot Point
TEC-500

Laser

Tuning Mirror

x2

x1

Technical Solution

x3

Grating

Tuning Mirror
x3

TEC-520

Laser

Gratingx2
x1

The emission wavelength of a laser isdefined by two features. The first condition is the cavity mode. The second condition is the amplification
range of the gain medium. Since
diode lasers have an extremely wide
gain region, it is necessary to put awavelength selective medium insideof the cavity like a grating. In order totune such a laser modehop-free, it isrequired to synchronize the grating
defined wavelength with the cavity
defined wavelength [1].

Pivot Point

98mm

5mm

180mm

80m

TEC-500m

Dimensions

Sacher Lasertechnik has realized thesynchronization between grating defined and cavity defined wavelength
by only a simple rotation of the mirror.
The adjustment of the pivot point isdone during the wavelength scanning
operation of our Littman/Metcalf laser
system according to our patent no.
5,867,512. Due to this special method,
we are able to ensure the best modehop free tuning behavior. An increaseof the output power and the total performance of the Littman/Metcalf laser
is achieved by using a high efficiency
grating and outcoupling the light of therear facet of the laser diode. With thisapproach, we are able to increase theoutput power to more than 100mW.

Technical Realization
The drawings on the left hand side
show the technical realization and thedimensions of the TEC-500 and theTEC-520 external cavity diode laser
systems. Due to using a alignment
insensitive cavity design and a flexmount concept, our Littman/Metcalf
laser diode systems are excellent
turn-key devices.
[1] M. G. Littman, H. J. Metcalf, Appl. Opt. 17, 2224, 1978

TEC-520

Automized Wavelength Scans
via remote Software!
Physical BasisPower [mW]

140130Coarse Tuning Range:

120

Wavelength vs. Output power

110
100
90
80760

765

770

775

780

785

790

795

Since the introduction of Therahertz
Generation, Differerence Frequency
Generation and broadband highr e s o l u t i o n s p e c t r o s c o p y, t h eenhancement of tunable Laser withhigh as well as automized tunability isrequired.

Wavelength [nm]130

Fine Tuning Range:

Technical Solution

Power [mW]

125

Wavelength vs. Output power
120
115
110
105
774.8

775.0

775.2

775.4

Wavelength [nm]Wavelength [nm]795790Tuning accuracy:

Tuning rate: 1 pm / step785

Motor step vs. Wavelength

780

Sacher Lasertechnik has realized amotorized Littman/Metcalf laser systemwich provides automated wavelengthscans via remote software.
Anincrease of the output power andcoarse tuning is achieved by using ahigh efficiency grating and outcoupling
the light of the rear facet of the laser
diode. With this approach, we are able
to increase the output power to morethan 100mW. Available wavelength are
currently 760nm... 1080nm. Furtherwavelength are under preparation..

775770765
760
05000

10000 15000 20000 25000 30000

Motor Position

Technical Realization&TEC-520

TEC-320

The picture on the left hand side show
the technical realization and thedimensions of the motorized
Littman/Metcalf external cavity diodelaser systems. Due to an alignment
insensitive cavity design and a highprecesily intelligent laser controller,
our Littman/Metcalf laser diodesystems is perfomred to your special
requirements.

Key Features of our
Littman/Metcalf Laser System
Side Mode Supression
0Beam Quality-10Signal [dB]-20-30-40-50

-60
760

770

780

790

800

Wavelength [nm]Example:Power: > 150 mW at 780nm
M 2 = 1.5 in both directions

In-house manufacturing of AR-coatings, Patent 6,297,066
In house manufacturing of anti-reflection coatings for diode lasers guarantees the best
performance for the complete laser system. for each type of application.

High passive stability
Realizing the pivot axis of the tuning grating and the cavity adjustement via flex-mounts
ensures the highest passive stability of our Littrow laser system. As a result, we achieve arobust and highly stable external cavity diode laser system with excellent values for the longterm laser linewidth.

Option: Single-mode fiber coupling
Due to the excellent mechanical stability of our Littrow laser system, we are able to perform
high efficiency fiber coupling with coupling efficiencies between 40% and 70% into singlemode polarization maintaning optical fibers. Optical isolators and angled fiber connectors(FC/APC couplers) are available upon request.

Specifications: http://www.sacher-laser.com/lmnspecs.php
Output Power10 .. 150 mW (depending on wavelength)

Wavelength

635, 655, 675, 685, 765, 780, 795, 810, 850, 895, 935,1060,1260, 1310, 1380, 1450, 1550, 1630, 1700 nm or customized

Wavelength Tuning

10 nm .. 120 nm (depending on wavelength)

Linewidth

500 kHz @ 20ms

Mode-hop Free Tuning> 30 GHz, typically > 100GHz

Side Mode Supression> 50 dB

Beam Quality M2< 1.5
specifications are subject to change without further noticeAbsorption / a.u.
Water Vapour
1,388.4

1,388.2

1,388.0

1,387.8

1,387.6

1,387.4

Wavelength / nm

Application Example
Water Vapor Spectroscopy
High resolution spectroscopy requires laser features like narrow linewidth, highpassive stability, exact adjustable wavelength as well as an excellent modehop
free fine tuning ability. The figure summarizes experimental data which have been
determined with our Littman/Metcalf laser system. The trace shows an absorption
signal of an optical water vapor concentration measurement in ambient air. The
total tuning range is 1nm with 1388nm as center wavelength of the scan.

About Sacher Lasertechnik
Company Profile
Sacher Lasertechnik is leading manufacturer of tunable external cavity diode lasers(ECDLs) with more than 13 years of experience. The product range includes antireflection coated diode lasers, ECDLs in Littrow and in Littman/Metcalf configuration
as well as driver electronics for the LD and sophisticated measuring electronics.
Please contact us with your measurement requirements. We would be proud
to support you with our competence.

Please contact us
Sacher Lasertechnik
GmbHRudolf-Breitscheid Str. 1-5
D-35037 Marburg/Lahn
Germany
Tel.: +49 6421 305 - 0
Fax: +49 6421 305299

Sacher Lasertechnik
LLC
5765 Equador Way
Buena Park, CA90620
U. S. A.
Tel.: 1-800-352-3639
Fax: 1-714-670-7662

Email: contact@sacher-laser.com
Web: http://www.sacher-laser.com

Application Example
Caesium Spectroscopy
High resolution spectroscopy requires laser features like narrow linewidth, highpassive stability, exact adjustable wavelength as well as an excellent modehop
free fine tuning ability. The figure summarizes experimental data which have been
determined with our Littman/Metcalf laser system. The lines shows an absorption
signal of the D2-line of Caesium. More demanding is the Doppler-free detection ofthe Lamb dips (Demtröder Laser Spectroscopy, Springer 1998). The enlargementshows the Doppler-free measurement of the Lamb -dip of the D2-line of Caesium.

About Sacher Lasertechnik
Company ProfileSacher Lasertechnik is leading manufacturer of tunable external cavity diode lasers(ECDLs) with more than 19 years of experience. The product range includes antireflection coated diode lasers, ECDLs in Littrow and in Littman/Metcalf configuration
as well as driver electronics for the LD and sophisticated measuring electronics.
Please contact us with your measurement requirements. We would be proud
to support you with our competence.

Please contact us
Sacher LasertechnikGmbH
Rudolf-Breitscheid Str. 1-5
D-35037 Marburg/Lahn
Germany
Tel.: +49 6421 305 - 0
Fax: +49 6421 305299

Sacher Lasertechnik
LLC5765 Equador Way
Buena Park, CA90620
U. S. A.
Tel.: 1-800-352-3639
Fax: 1-714-670-7662

Email: contact@sacher-laser.com
Web: http://www.sacher-laser.com