Detector nonlinearity in Fourier transform spectroscopy

Abstract

Spectral distortion due to the nonlinear response of HgCdTe detectors is well known. Methods for removing such features are discussed. Nonlinear response in HgCdTe detectors is a well known complication in midir Fourier transform spectroscopy; methods of removing the spectral artifacts created by nonlinearity are less well understood. While the instrument and experiment may be designed so that the desired spectrum is properly sampled, non-linearity introduces spectral features that lie outside the intended bandpass and consequently are undersampled and subject to aliasing. Consequently, in cases where nonlinear response may be expected it is essential that optical filters be chosen with the nonlinear harmonics in mind. Several examples of nonlinearity are considered, with practical examples drawn from the ATMOS data set.