Fourier transform heterodyne spectroscopy: a simple novel technique with ultrahigh (150 mHz) resolution

Abstract:

Light beating spectroscopy has been used from the early days of the laser to study light scattering. By detecting the beating signal between the scattered light and a 'local oscillator' field derived from the same laser, resolving powers of 10^14 have been achieved. The Fourier transform heterodyne spectroscopy presented here is simpler and more direct than the conventional heterodyne techniques using autocorrelators or spectrum analyzers.