Spectroscopic Applications of Frequency Modulated Dye Lasers

Abstract

My interest in frequency modulated lasers was stimulated when I was a visiting scholar at Stanford in the Schawlow/Hänsch group from October 1977 to February 1979. During the first part of my visit to Stanford I worked with Jim Eckstein on the use of a coherent train of mode-locked dye laser pulses as a source for Doppler-free coherent multiple pulse spectroscopy [1], The idea behind these experiments was that a mode-locked laser could provide a source of coherent radiation with high peak power but yet could be used for high-resolution spectroscopy. At Jim’s PhD viva, Tony Siegman asked if he thought that frequency modulated lasers could be used for this kind of spectroscopy. On hearing about this question, most of us smiled knowingly and then began to wonder exactly what is a frequency modulated laser! I can’t remember how Jim managed to extricate himself from this Question but the next day several of the people involved in this project went off to the library to find out about frequency modulated lasers.