USE OF AN ALIASING ARTEFACT IN FT SPECTROMETRY TO DISTINGUISH BETWEEN PULSED AND CONTINUOUS EMISSIONS OCCURING IN THE SAME SOURCE

Abstract
Spectral aliasing can be usefully employed to differentiate between emission from pulsed and continuous sources when recording spectra on a continuous scanning Fourier transform spectrometer. Examples are given using a pulsed copper vapour laser to excite fluorescence in the presence of strong blackbody radiation. The continuous emission is sampled at regular optical path differences [MATH] and shows no aliasing in the spectral range [MATH]. The pulsed emission is slaved to the interferometer at a frequency which is half that of the interferometer sampling rate producing a duplicate of the pulsed spectrum [MATH] at [MATH]. The two can thus be distinguished, provided that the ghosts appear in a spectral region which contains no true lines.