Detector nonlinearity correction scheme for the LPMA balloonborne Fourier transform spectrometer

The Limb Profile Monitor of the Atmosphere (LPMA) instrument is a Fourier transform spectrometer designed to record stratospheric (and in some cases tropospheric) absorption spectra from a balloon gondola. This spectrometer operates with two-detector output optics (photoconductive HgCdTe and photovoltaic InSb, Liquid-nitrogen cooled). The response of the HgCdTe detector becomes nonlinear for high photon fluxes, which is the case for solar occultation. We have designed a processing scheme, based on the minimization of out-of-optical-band spectral artifacts, to correct for the effect of nonlinearity in the useful spectral range. The method is explained, and sample results are presented for spectra recorded in different balloon flight conditions and with two different HgCdTe detectors. (C) 1998 Optical Society of America.