Optical System Transmittance Detection

The transmission of the optical system is the ratio of the outgoing light flux and the incident light flux. Single-channel transmission of traditional detection methods, have been detected signals are DC signals, so vulnerable to fluctuations in light, background light and all kinds of noise, testing accuracy is not high, and the operation inconvenient. In order to reduce the affection of the background light on the system measurement accuracy, and the measurement must be completed in the dark room. In this paper, the test beam have been modulated, making it the exchange of signals with certain frequency, and uses dual-beam cross-correlation detection method, that is, the reference light signal and the test light signal are tested by the same frequency reference signal with cross-correlation operations. This method can effectively avoid the fluctuations in light, background light and all kinds of noise, can be achieved in the light transmittance of optical system for field measurements, and can reach higher measurement accuracy, is more convenient to use.