UV/VIS Wavelength Generation
SHG
External Housing (FC-EXH)
All Dimensions in mm. Specifications are subject to change without notice.
Second Harmonic Generation
The Sirah Frequency Conversion Unit (FCU) is designed to frequency double a dye laser beam. Typically, the dye laser is operated in the visible spectral range. This frequency is doubled by a BBO crystal followed by a compensator. The crystal’s angle is tuned to maintain phase matching inside of the crystal. An arrangement of 2 or 4 Pellin-Broca prisms (WS-2 or WS-Auto, please order separately) separates the UV from the fundamental beam. The FCU may be integrated into the laser housing (not possible for the Cobra model) or attached externally to the laser (add FC-EXH housing). All crystals, compensators and Pellin-Broca prisms are fully adjustable, making the unit easy to use.
THG
All Dimensions in mm. Specifications are subject to change without notice.
Third Harmonic Generation
The Sirah THU-205 (third harmonic unit) is designed to generate laser radiation in the UV wavelength range, from 197 to 260 nm, by third harmonic generation (THG). It is operated together with a Nd:YAG pumped dye laser, either a PrecisionScan or a Cobra-Stretch model.
Principles
The dye laser is operated in the red spectral range, from 591 to 780 nm. Its output beam is first frequency doubled by a temperature stabilized BBO crystal. Then, the resulting UV beam is sum frequency mixed with the residual dye laser beam in a second temperature stabilized 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 wavelength range of the THU-205. Alternativly a wavelength separation with four
Pellin-Broca prisms made of very high quality CaF2 can be used. This unit is mounted vertically behind the THU-205 (+ 171 mm in length). It can be mounted also horizontally behind the doubling unit for separation of the second harmonic generation (SHG).
MAD
All Dimensions in mm. Specifications are subject to change without notice.
Mixing After Doubling
The Sirah MAD-195 (mixing after doubling) is designed to generate laser radiation in the UV wavelength range from 190 nm to 202 nm. It is operated together with a Cobra-Stretch or PrecisionScan dye laser, pumped by an injection seeded Nd:YAG laser.
Principles
The dye laser is operated in the blue spectral range, from 462 nm to 490 nm. Its output beam is first frequency doubled by a BBO crystal. Then, the resulting UV beam is sum frequency mixed with the residual fundamental Nd:YAG radiation. A set of 4 dichoic mirrors separates the generated UV beam from the two incoming beams. Additionally, the MAD-195 unit may easily upgraded to a third harmonic generation unit (THU-205), giving access to wavelength from 197 nm to 212 nm..
SFM – 355 nm
Sum Frequency Mixing with 355 nm
The SFM-355 mixing unit is designed to generate laser radiation in the UV wavelength range, from 216 nm to 241 nm. It is operated together with a Cobra-Stretch or PrecisionScan dye laser, pumped by an injection seeded frequency doubled Nd:YAG laser. Generation of wavelengths around 220 nm by mixing is an alternative to the use of frequency doubled (SHG) blue dyes pumped by the frequency tripled YAG. The advantage of this approach is the superior lifetime of the used dyes and the smaller spectral bandwidth of the generated UV radiation. On the other side a seeded pump laser is required and the set-up is more complex.
Principles
The dye laser is operated in the red spectral range, from 545 nm to 751 nm. Its output beam is sum frequency mixed with the frequency tripled Nd:YAG radiation. A pair of Pellin-Broca prisms separate the generated UV beam from the dye and Nd:YAG beams.
Tuning curves with di erent dyes, when using approximately 600 mJ @ 532 nm for dye pumping and 300 mJ @ 355 nm for mixing.
SFM – 1064 nm
Sum Frequency Mixing with 1064 nm
The SFM-1064 mixing unit is designed to generate laser radiation in the UV wavelength range, from 360 nm to 440 nm. It is operated together with a Cobra-Stretch or PrecisionScan dye laser, pumped by an injection seeded frequency doubled Nd:YAG laser. Generation of wavelengths around 400 nm by mixing is an alternative to the use of blue dyes pumped by the frequency tripled YAG. The advantage of this approach is the superior lifetime of the used dyes. On the other side a seeded pump laser is required, the set-up is more complex, and overall effciency is lower than with blue dyes.
Principles
The dye laser is operated in the red spectral range, from 545 nm to 780 nm. Its output beam is sum frequency mixed with the residual fundamental Nd:YAG radiation. A set of four Pellin-Broca prisms separates the generated UV beam from the dye and Nd:YAG beams.
All Dimensions in mm. Specifications are subject to change without notice.
