| Passive
q-switching has become widely used technique in solid state lasers development.
The application of saturable absorbers simplifies considerably laser design,
makes it more compact and cheap. The saturable absorbers became successfully
applied in diode pumped microchip lasers. |
|
Cr+4:YAG passive Q-switch |
|
Cr+4:Y3Al5O12
or Cr+4:YAG - is a material that can be
used as an active media for CW, pulsed or self mode-locked tunable NIR
solid-state lasers with tunability range 1340 - 1580 nm as well as a media
for Q-switching in lasers with operating wavelength at 950 - 1100 nm.
It is particularly useful in practical applications because of convenient
absorption band of Cr+4around 1 mm which
gives possibilities to pump it by regular Nd:YAG lasers. A saturation
of absorption in the band at 1060 nm is useful for application in small
sized Nd:YAG oscillators with flash lamp or laser diode pumping instead
of based on dye or LiF:F-center passive Q-switches. Using the Cr+4:YAG
crystal the self mode-locking (KML) regime is achievable. It gives an
opportunity to build the laser source with pulse duration shorter then
100 fs at 1450 - 1580 nm.
Finally, its high thermal and radiation stability as well as excellent
optical and mechanical properties will give you an opportunity to design
reliable devices based on the crystal.
Technical Specifications:
| Wavelength,
nm |
950 - 1100
nm |
| Initial transmittance,
% |
15 - 90 |
| Initial absorption
coefficient, cm-1 |
0.05 - 3.00 |
| Aperture, mm |
5 - 12 |
| Contrast |
> 8 - 10 |
| Optical length,
mm |
1 - 40 |
| Damage threshold,
J/cm2 |
> 4 |
| Long-term stability |
> 15 years |
|
|
|
GSGG : Cr4+ passive Q-switch |
|
|
Gadolinium-scandium-gallium garnet doped with chromium and magnesium
GSGG:Mg:Cr4+ is a material for passive
Q-switching in 1 µm region. The valence state of chromium ion
Cr4+ is provided by use of charge
compensator. The crystals are grown by Zchochralski method in argon-oxigen
atmosphere. Crystals of GSSS:Mg:Cr possessing the contrast parameter
close to the one of YAG:Cr4+ have
some advantages such as: possibility to provide necessary initial
transmission at less thickness (typical thickness is about 1mm),
transparency in the visible range which simplifies the alignment
procedure. |
SPECIFICATION:
| Initial transmission
|
5 - 95 % |
| Absorption index
at the wavelength of 1.067 µm |
0.2-10 cm-1 |
| Contrast |
6 - 7 |
| Thickness |
0.5 - 5 mm |
| Diameter |
6 - 9 mm |
| Relaxation time
of the exited state (4A2
→ 4T1(4F)
absorption) |
200 ns |
Application: for short-pulse
lasers of IR spectral range
Publications:
R.Buzelis, A.Dementiev,
E.Kosenko, E.Murauskas, F.Ivanauskas, M.Radziunas "Determination of
absorption cross sections of Cr4+:GSGG and Cr4+:YAG passive Q-switches
at the generation wavelength of Nd:YAG laser", Lithuanian Journal of
Physics, 37(4), pp 291-298, 1997
|
|
|
YAG:V3+ passive Q-switch |
|
|
The crystals of Yttrium-Aluminum Garnet doped with three-valence
vanadium V3+ in tetrahedral position
suggest efficient q-switching for lasers operating in 1.3 µm
region. The absorption band between 1.0 - 1.5 µm is attributed
to 3A2
→3T2
transition of V3+ ion in tetrahedral
position of garnet lattice. The crystals are grown by oriented crystallization
method. Concentration of V3+ in tetrahedral
position is controlled by growth and annealing conditions.The efficient
q-switching of lasers operating at 1.3 micron has been obtained
with a number of active mediums such as YAG:Nd, YVO4:Nd,
KGd(WO4)2:Nd
under flash-lamp and laser diode pumping. |
SPECIFICATION:
| Initial transmission
|
5 - 95 % |
| Contrast |
5 - 6 |
| Thickness |
0.5 - 5 mm |
| Diameter |
5 - 7 mm |
| Ground-state
absorption cross-section at 1.32 µm |
7.3 x
10-18 cm2 |
| Ground-state
absorption cross-section at 1.06 µm |
3.0 x
10-18 cm2 |
| Relaxation
time of the exited state (3T2
→ 3A2
absorption) |
20 ns |
Application:
for short-pulse lasers of IR spectral range 1.06 - 1.4 µm
Publications:
A.M.Malyarevich,
I.A.Denisov, K.V.Yamashev, V.P.Mikhailov, R.S.Conroy, B.D.Sinclair,
"V:YAG - a new passive Q-switch for diode pumped solid state lasers",
Appl. Phys. B 67 (1998), p. 555
|
|
|
Co+2:MgAl2O4 passive Q-switch |
|
Spinel
crystal is a material having high optical damage threshold and low optical
losses in 1.3 - 1.6 µm spectral range. Co2+-activated
MgAl2O4
(Co:MALO, Co:spinel) can be used as a media for passive Q-switch of lasers
which operate in the spectral range of 1.3 - 1.6 µm, for example 1.32
µm and 1.44 µm Nd:YAG lasers, 1.31 µm iodine lasers and especially
1.54 µm erbium glass lasers.
High enough absorption cross-section of Co+2
ions together with practical absence of excited state absorption makes
this material a very efficient passive Q-switcher (that does not require
intracavity focusing) for various types of erbium glass lasers, including
diode-pumped microchips.
Technical Specifications:
| Absorption
band, µm |
1.3 - 1.6 |
| Operating transition |
4A2
-4T1
(4F) |
| Absorption
cross-section at 1.54 µm, cm2 |
2 x 10-19 |
| Bleached state
lifetime at 300°K, ns |
200 |
| Dopant level,
cm-3 |
2 x
10-17- 3 x
1019 |
| Initial transmission,
% |
10 - 99 |
| Initial absorption
coefficient at 1.54 µm, cm-1 |
0.06 - 10 |
| Aperture, mm |
5 - 12 |
| Plate thickness,
mm |
0.2 - 5 |
| Co+2:MgAl2O4
passive Q-switch |
Cat.-No.: D-120-01 |
|
