- Unit: Faculty of Physics
- Keywords: Total integrated scattering test, nanosecond laser, Nd:YAG, Ekspla, NL202, roughness evaluation, LabSphere Ulbricht, Hamamatsu, National Instruments, OceanOptics, 1064 nm, 532 nm, 355 nm
- Responsible person: Prof. Valdas Sirutkaitis, +370 5 236 6005,
Station is suitable for the evaluation of total integrated scattering from the whole surface and surface roughness of different optical elements (mirrors, filters, optical substrates, radial polarization converters), which are designed for 1064 nm, 532 nm and 355 nm laser radiation).
The total integrated scattering test station consists of: LabSphere Ulbricht type integrating sphere (spectral range 0.35-1.4 mm), closed-loop air cleaning system (EkoFiltras) with three-stage filters. ISO 6 cleanliness is achieved in the HEPA14 camera. Measurements can be performed using first (1064 nm), second (532 nm) and third (355 nm) harmonics of a nanosecond Nd:YAG Q-switched laser (Ekspla NL 202), producing 9 ns pulses with up to 2 mJ pulse energy at a 1 kHz repetition rate. The station can perform scattering loss measurements on samples with a diameter from 12.7 to 28 mm and thickness from 2 to 6 mm. Sample positioning is possible ±15 mm in x and y directions. Two photomultipliers are used: Hamamatsu H5784-20 for 350 - 900 nm spectral range and PMT R5108 for 400-1200 nm. A National Instruments BNC-2110 16 section converter, optimized for short-pulse registration, is integrated for the registration of the scattered and incident radiation. A computer with software is also integrated in the system. For our measurements, we use the OceanOptics WS-1-SL standard, scattering >98% light in 250 – 1500 and 95% in the 250-2200 nm spectral range.