Bauteile für KrF, XeCl und XeF Laser

Standard Components

  • Oxide coatings for high mechanical stability and low straylight losses
  • Laser mirrors (R > 99% at 248nm, R > 99.5% at 308nm and 351nm)
  • 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 248nm 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 248nm and 308nm, R > 96% at 351nm)
  • High quality mirror substrates, windows and lenses of CaF2 (248nm excimer grade or UV quality, SCHOTT AG)
  • 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*Lifetime test
HR (0°, 248 nm)oxides> 99 % 10 J/cm2, 1 - on - 1,20 ns 5 J/cm2, 1000 - on - 1
HR (45°, 248 nm)oxides> 99 % (random pol.) 10 J/cm2, 1 - on - 1,20 ns
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 ***
*Measurements were performed at Laser Labor Göttingen and at Friedrich-Schiller Universität Jena
**Energy density: 100 mJ/cm2, rep. rate: 100Hz, pulse duration: 15ns; tested at COHERENT AG, München
***Energy density: 55 mJ/cm2, rep. rate: 100Hz, pulse duration: 15ns; tested at COHERENT AG, München