Absorption / Scattering

Absorption

According to ISO 11551 absolute absorption of optical components is measured by a high resolution (UV-) laser calorimeter which enables the determination of linear as well as non-linear absorption losses in optical materials. For the used irradiation wavelengths (193 nm, 248 nm, 351 nm) a fast evaluation of the long-term behavior of DUV optics at low energy density is possible.

• Precise measurement of absorption according to ISO 11551 (ppm sensitivity)
• Determination of linear and two-photon absorption coefficients
• Observation of aging and degradation (e.g. color center formation)
• Non-destructive quality control of excimer laser optis

Scattering

Losses in UV-optics due to scattering are evaluated with a special setup consisting of an excimer laser as light source and a coated Ulbricht's sphere  as integrating detector.

• Determination of total scatter (TS) in the UV spectral range
  
• Sensitivity: <1 ppm at 248 nm, <30 ppm at 193 nm
• 2D mapping of scatter distribution

Further reading:

 Flyer: Characterization of UV optics
 Appl. Phys. B; Comparative studies of absorptance behaviour of alkaline-earth fluorides
 Opt. Comm.: Surface and bulk absorption in CaF2 at 193 and 157nm