|
As a novel saturable absorbing material, Tetravalent
Chromium-doped Yttrium-Aluminum Garnet (Cr4+:YAG) is an
excellent and convenient crystal for passively Q-switching
diode-pumped or lamp-pumped Nd:YAG, Nd:YVO4, Nd:YLF or
other Nd and Yb doped lasers (wavelength from 1.0 to 1.2 m m). Due to
its specific properties: broad absorption band (at the vicinity of 1 m
m), high damage threshold (> 500 MW/cm2), long lifetime,
large absorption cross section (in the near IR), good thermal
stability and heat dissipation (especially at high repetition rates)
and easy operation, Cr4+:YAG will replace the saturable
absorbers such as Dye cells and acetate films, and color-center
crystal LiF:F2-, which are commonly used as
passive Q-switching materials, and meet the requirements of reliable,
simple, compact and effective laser systems, for example,
range-finders and military systems.
When used for passive
Q-switching of Nd:YAG laser, a pulse width of 8.3 ns and a Q-switching
efficiency of 56.9% were obtained. Cr4+:YAG was
successfully used for the Q-switching of the slab laser with a big
cross-section, Raman shift 1.54 m m laser with a high repetition and
the LD-pumped CW Nd:YVO4 laser for the first time.
Cr4+:YAG is also a laser crystal with
tunable output wavelength from 1.35 m m to 1.6 m m. It can generate
ultrashort pulse laser (to femtosecond) when pumped by Nd:YAG laser at
1.064 m m.
Beijing Gospel OptoTech Co. (GOT) now provides lots of
Cr4+:YAG discs used as with high optical quality and the
initial transmission from 1% to 99%. Diameters of Cr4+:YAG
discs are from 2 mm to 25 mm, and thickness from 0.2 mm to 10 mm. We
also supply Cr4+:YAG rods with 2〜10
mm diameters and up to 80 mm length as tunable laser host.
Basic Properties
¨ Density : 4.56/cm3
¨ Chemical Formula :
Cr4+:Y3Al5O12
¨ Crystal Structure :
Cubic
¨ Dopant
Concentration : 0.6-3.0 mol%
¨ Mohs Hardness : 8.5
¨ Refractive Index :
1.820 @1.064 m m
¨ Damage Threshold :
> 500 MW/cm2
¨ Absorption of
ground state level : 5.7x10-18 cm2
¨ Absorption of
exited state level : 8.0x10-19 cm2
Standard Specs. of Cr4+:YAG
Crystals
¨ Cr4+
doping level : 0.5 〜
3.5 mol%
¨ Standard Aperture :
f 2~25 mm or 2x2 ~ 18x18 mm2
¨ Initial
Transmission : 1.0% ~ 99.0%
¨ Wavefront
Distortion : l /8 @633 nm
¨ Flatness : l /10
@633 nm
¨ Parallelism : < 10
arc seconds
¨ Perpendicularity :
< 5 arc minutes
¨ Scratch/Dig Code :
10/5 per MIL-O-13830A
¨ Barrel Finish : 50
- 80 micro-inch (RMS)
¨ Anti-Reflection
Coating : R < 0.1% @1.064 m m per surface
Special Notes for Cr4+:YAG
Crystals
· Other kinds of
coatings (AR or HR coatings) are available upon request.
· The diameter,
initial transmission (or optical density) and
coatings shall be offered while purchasing Cr4+:YAG
discs as passive Q-switch components.
· GOT has enough
quantities of Cr4+:YAG passive Q-switch discs (9 mm
diameter) with AR coating at 1.064 m m and versatile initial
transmission in stock, and can deliver in 24 hours.
· Free samples are
available from GOT upon request, for the purpose of long term
technical and business cooperation, as well as the developments of new
applications.
· The latest technical
information of Cr4+:YAG crystal and its applications will
be provided.
|
