Optical method for resolution enhancement in photodiode array Fourier transform spectroscopy

In this paper, we propose a method for optically improving the resolving power of the photodiode array Fourier transform spectrometer [ T. Okamoto S. Kawata S. Minami , Appl. Opt.23, 269 ( 1984)] rather than using mathematical superresolution techniques. The spatial frequency of the interferogram is modulated by the dispersing element added to the triangular common path interferometer so that the spectral resolution is enhanced in the effective spectral range. Since the modification of the method is only the addition of the dispersing optical element to the original optical setup, the advantages of the simple, stable, and easy optical alignment and the large optical throughput with the photodiode array Fourier transform spectroscopy are maintained. Experimental results demonstrate the resolution enhancement by the proposed method with the emission spectra of a low pressure mercury lamp and a cadmium lamp.