Components for KrF, XeCl and XeF Lasers
Standard Components
- Oxide coatings for high mechanical stability and low straylight losses
- Laser mirrors (R > 99 % at 248 nm, R > 99.5 % at 308 nm and 351 nm)
- High quality mirror substrates, windows and lenses of fused silica
- PR coatings with tolerances of
- ± 2 % for R = 10 … 30 %
- ± 3 % for R = 30 … 75 %
- ± 2 % for R = 75 … 90 % and
- ± 1 % for R > 90 %
- Development and production of customer specific components
Figure 1: Reflectance and transmittance spectrum of a 248 nm turning mirror (AOI = 45°) for random polarized light Figure 2: Transmittance spectra of a variable attenuator for 308nm at different AOI (a) and transmittance vs. AOI at 308 nm (b); the transmittance varies from T > 85 % at AOI = 0° to T = 2 ± 1 % at AOI = 45° (unpolarized light) Fluorine Resistant Cavity Optics
- Fluoride coatings and CaF2 substrates for high stability against fluorine and chlorine
- laser mirrors (R > 98 % at 248 nm and 308 nm, R > 96 % at 351 nm)
- High quality mirror substrates, windows and lenses of CaF2 (248 nm excimer grade or UV quality)
- PR coatings with tolerances of
- ± 2 % for R = 10 … 30 %
- ± 3 % for R = 30 … 75 % and
- ± 2 % for R = 75 … 90 %
Figure 3: Reflectance spectrum of a fluoridic KrF laser mirror (a) and an output coupler with R = 50 ± 3 % (b) Technical Data of KrF, XeCl and XeF Laser Components
Coating | Materials | Reflectance | Damage threshold |
---|
HR(0°, 248 nm) | oxides | > 99 % | 10 J/cm2, 1-on-1, 20 ns; * 5 J/cm2, 1000-on-1, 20 ns * |
HR(45°, 248 nm) | oxides | > 99 % (random pol.) | 10 J/cm2, 1-on-1, 20 ns * |
* | Measurements were performed at Laser Labor Göttingen and at Friedrich-Schiller-Universität Jena |
Coating | Materials | Reflectance | Lifetime test |
---|
HR(0°, 248 nm) | fluorides | R > 98 % | 2 x 108 pulses ** |
PR(0°, 248 nm) | fluorides | R = 50 ± 3 % | 2 x 108 pulses ** |
PR(0°, 248 nm) | fluorides | R < 0.25 % | 2 x 108 pulses ** |
HR(0°, 308 nm) | fluorides | R > 98 % | 2 x 108 pulses *** |
HR(0°, 351 nm) | fluorides | R > 96 % | 2 x 108 pulses *** |
PR(0°, 351 nm) | fluorides | R = 25 ± 3 % | 2 x 108 pulses *** |
** | Energy density: 100 mJ/cm2, rep. rate: 100 Hz, pulse duration: 15 ns; tested at COHERENT AG, München |
*** | Energy density: 55 mJ/cm2, rep. rate: 100 Hz, pulse duration: 15 ns; tested at COHERENT AG, München |