Zero-crossing signal averaging system for Fabry–Perot interferometry

Abstract

The detailed design and performance of a zero‐crossing signal averaging scheme for Fabry–Perot (FP) interferometry, which has been successfully applied to the study of Rayleigh–Brillouin scattering of gases, are presented. The system, which locks the start of each scan of a multichannel scaler (MCS) to the laser frequency, and assigns a definite frequency to each channel of the MCS, can be adapted to any piezoelectrically scanned FP interferometer. It has a variable scan rate permitting magnification of the spectrum over regions of interest and also provides sample pulses for synchronously advancing the memory address of standard multichannel scalers with the scanning FP interferometer. The principal features of our design are simplicity, adaptability, and low cost.