Applicability of triangular common path interferometric spectroscopy to pulsed and extended light source

Abstract

Fourier transform spectrometer was applied to a spatially incoherent extended and pulsed source. The triangle common path interferometer having two sides of about 70 mm long was coupled with a image intensifier (I.I.) interfaced to a 16 bit microcomputer by the 512 channel Reticon linear array. The tube type I.I. having very high optical gain showed image distortion, though the proximity focus I.I. did not show this at all. Inequities of sampling intervals of the interferogram in the former I.I. caused the distorsion of calculated spectra. Fourier transformation was modified by using measured friges of equal thickness of a He-Ne laser. Despite of widening the aperture for the source, the resolving power was kept constant and the spectral peak height increased almost proportionally. Single pulse (a frequency doubled ruby laser; 347 nm, 20 mj, 10 ns)-excited Ramman spectra of acetonitrile and methanol were obtained with a moderate intensifier gain. The methods of improving the resolving power (about 100 cm-1) were discussed. A new possibility for rejecting fluorescence and Rayleigh scattering was mentioned. © 1988, The Japan Society for Analytical Chemistry. All rights reserved.