Rayleigh backscatter control apparatus and method

摘要

An analyzer for analyzing chemical properties of a specimen using optical coupling and sensing, has a narrow band light source and an optical probe that is in contact with the specimen. Detectors are used for providing electrical outputs as a function of a parameter of the specimen, and an optical path couples light from the light source to the probe and also couples Raman scattered light from the specimen and Rayleigh scattered light from the specimen to separate detectors. An analyzer circuit is coupled to the detectors to provide outputs as a function of the electrical signals received, and one of the detectors is connected to a signal conditioning circuit for controlling the input of the light source and includes an asymmetric discrimination circuit configured to distinguish positive going fluctuations from negative going fluctuations in the output from the detector.