Knowledge Bank

A new type of high resolution Raman spectroscopy is described and applied to the study of details of laser induced Raman spectra. With the increasing availability of continuous-wave lasers, the determination of Raman spectra will be much facilitated. For resolving lines which are separated by less than $109$ cycles/sec apart, a new method of spectroscopy is described. This method may be used in conjunction with the more conventional ones. In this method, the scattered light is detected with a square law detector such as a photo-multiplier and the separations, between lines are determined by measurement of the powers at the various beat frequencies. To remove the limitations imposed by the presence of the shot noise of cross-correlated. Insofar as the signals are concerned, the process corresponds to autocorrelation and very low signals may be detected in this manner.