Sirah
Third Harmonic Generation
The Sirah THU-205 (third harmonic unit)
is designed to generate laser radiation
in the UV wavelength range, from 197 to
212 nm, by third harmonic generation
(THG). It is operated together with a
Nd:YAG pumped dye laser, either the
PrecisionScan or the Cobra-Stretch
model.
Principles
The dye laser is operated in the red
spectral range, from 591 to 636 nm. Its
output beam is first frequency doubled
by a temperature stabilized KDP crystal.
Then, the resulting UV beam is sum
frequency mixed with the residual dye
laser beam in a BBO crystal. A set of 4
dichroic mirrors separates the generated
UV beam from the two incoming. Due to
the short wavelength, different dichroics
sets are necessary to cover the entire
wavelength range of the THU-205.
Additionally, wavelengths from 206 to
370 nm may be generated by second
harmonic generation (SHG), with the dye
special waveplate
dump
532 nm
Oscillator
Pre-Amp
Main Amp
(EBP)
615 nm
Nd:YAG Laser
compensator
doubling
crystal (KDP)
Dye Laser
UV
output
tripling
crystal (BBO)
dichroics for separation
THU-205
Tuning Range
With DC-195 dichroics set
190 - 200 nm
With DC-205 dichroics set
200 - 210 nm
1,9
Rh B &
Rh 640
1,8
Rh 640 &
Rh B
DCM
Energy / mJ
1,6
1,4
1,2
1,0
0,8
0,6
0,4
0,2
0,0
197
199
201
203
205
Wavelength / nm
Tuning curves with different dyes, when pumped with approximately
500 mJ @ 532 nm. At a given wavelength, full energy is only obtained
if the correct dichroics set for beam separation is installed.
207
209
211
Sirah
Third Harmonic Generation
Energy Output
Pump Laser
Dye Laser
Output Energy
800 mJ @ 532 nm
PrecisionScan-GA-24
3.0 mJ
800 mJ @ 532 nm
PrecisionScan-DA-24
2.7 mJ
500 mJ @ 532 nm
Cobra-Stretch-GA-24
1.8 mJ
500 mJ @ 532 nm
Cobra-Stretch-DA-24
1.7 mJ
UV energy output at 205 nm, with DC-205 dichroics set. See tuning curve for output energies at other wavelengths.
General Characteristics
Wavelength range with THG
Wavelength range with SHG 1)
197 - 212 nm
206 - 220 nm (SHG-205 crystal, included)
215 - 280 nm (SHG-220 crystal, optional)
260 - 370 nm (SHG-260 crystal, included)
650 mJ @ 532 nm
1000 mJ @ 532 nm 2)
2400 lines / mm grating recommended
1800 lines / mm grating possible
10 Hz recommended
look-up table (Autotracking optional)
vertical, > 98 %
3 - 6 mm, depending on amplifier cell type
< 0.5 mrad
Maximum Pump Energy
Dye Laser Resonator
Repetition Rate
Crystal Tuning Mode
UV Beam Polarization
UV Beam Diameter (typical)
UV beam Divergence
1) single crystal operation, requires WS-2 or WS-4 Pellin-Broca unit
2) with secondary main amplifier, only possible with PrecisionScan dye laser
Dimensions
942
35
872
THU-205 (side view)
158
277..310
210..235
210..235
332
polarization
35
460
495
Laser- und Plasmatechnik GmbH
THU-205 (uv output end)
INTERNATIONAL DISTRIBUTOR
An der Feuerwache 10
D - 41564 Kaarst
THU-205 (dye input end)
All Dimensions in mm
Specifications are subject to change without notice
VISIBLE AND INVISIBLE
LASER RADIATION
AVOID EYE OR SKIN EXPOSURE TO
DIRECT OR SCATTERED RADIATION
CLASS 4 LASER PRODUCT
Phone: +49 (0)2131. 66 06 51
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Fax:
+49 (0)2131. 66 80 95
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9/2003
http://www.sirah.com
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