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
248nm turning mirrorFigure 1: Reflectance and transmittance spectrum of a 248 nm turning mirror (AOI = 45°) for random polarized light
Variable attenuator for 308nmFigure 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 %
Variable attenuator for 308nmFigure 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

CoatingMaterialsReflectanceDamage 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

CoatingMaterialsReflectanceLifetime test
HR(0°, 248 nm)fluoridesR > 98 %2 x 108 pulses **
PR(0°, 248 nm)fluoridesR = 50 ± 3 %2 x 108 pulses **
PR(0°, 248 nm)fluoridesR < 0.25 %2 x 108 pulses **
HR(0°, 308 nm)fluoridesR > 98 %2 x 108 pulses ***
HR(0°, 351 nm)fluoridesR > 96 %2 x 108 pulses ***
PR(0°, 351 nm)fluoridesR = 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