The absolute calibration of high-precision optical flats across a wide range of spatial frequencies

We analyse the applicability of the two-flat-test calibration method across wide spatial frequency range based on its calculated accuracy. A number of simulations have been performed to determine the accuracy of the absolute calibration. The simulation results show that the two-flat-test calibration method is applicable to surfaces within the spatial frequency range from 1.67×10−1 to 1.67×10−3 mm−1

Adaptation of the Er-Yb microchip laser for use in phase-sensitive optical time domain reflectometry

We report on the experiments related to the Er-Yb microchip laser setup with fiber diode pumping. The main goal is a new radiation source for the use in the phase-sensitive optical time domain reflectometry (-OTDR) development