Performance of a New Photoelectric Detection Method for High-Resolution Optical Spectroscopy. I. Investigation of Basic Characteristics

Recently, Pao, Zitter, and Griffiths reported on a new method of detecting light signals of low intensity. The results of a more detailed investigation of the nature and characteristics of this method are presented in this paper. In this new method, the conventional slowly varying signal is discarded and the mean of the square of the fluctuations is detected instead. It is shown that in principle the incident light can be detected equally well this way. Furthermore this method is effective in discriminating against dark-current noise and in practice seems to perform better than dc and phase-sensitive detecting systems at low light intensities.