A method to measure the beat frequency of weak light
一种测量弱光拍频的方法

A method is proposed for measuring the beat frequency of weak light based on pho ton correlation measurements. In contrast to conventional techniques this method is not limited by the response time of the detector or preamplifier, and can me asure frequencies on the order of 10GHz without the need of a frequency spectrum analyzer. Moreover, extremely low light intensities may be measured.