The use of pressure controlled Fabry-Perot interferometer with linear scanning of data for Brillouin-type experiments

The article presents results from work with Fabry-Perot interferometers in Brillouin laser light scattering experiments, where optical signals of very low level intensity are observed. The information presented here can be useful in other types of optical experiments where scanning in the Fabry-Perot interferometer spectral range has to be used. In such situations the shape of spectral lines as well as their relative distances can be detected. The key to the solution presented here is the use of a silicon-membrane pressure sensor coupled to a pressure chamber. It makes it possible to view spectral lines equally spaced after nonlinear flow of air from a chamber where the Fabry-Perot interferometer is placed. Linear scanning in the spectral range equal to a frequency of about 150 GHz is possible. The method can be applied to Fabry-Perot's etalons, very frequently produced some years ago. Now it should find new fields of application, in a simple and cost effective way, in student laboratories as well as in other research institutions. (C) 2000 American Institute of Physics. [S0034-6748(00)01808-6].