| Popis: |
A set-up for the reflectance measurement of materials or optical system at 1.06 and 10.6 micrometers wavelengths is presented. It is based on the reflection measuring method of the Institut fuer Strahlwerkzeuge in Stuttgart, Germany. In contrast to it, we used an acousto- optical modulator instead of a mechanical chopper mirror. Advantages are the higher maximum chopper frequency of 100 kHz and the absence of mechanically moved parts. In consequence, the signal to noise ratio is improved. Some problems arise form the diffraction efficiency of the modulator and form the generation of higher order diffraction. In this script first results are presented on the calibration of the measuring set-up, the measuring procedure and the calculation of the actual reflectance from the measured data. |
