Minimization of optical non-linearities in Fourier transform-infrared microspectroscopic imaging

Abstract

This paper describes the FT-IR microspectroscopic imaging measurements of 5-μm diameter particles and demonstrates the associated optical non-linearities, due to chromatic aberration and diffraction. FT-IR microscopes with single-element detector use image masking in order to minimize the optical effect due to diffraction. Image masking cannot be used in the focal-plane array detector microscopes. The work presented here demonstrates that, through the application of multivariate curve resolution (MCR), the chemically significant information can be separated from the optical non-linearities. An improvement of the spatial resolution is achieved through the use of multivariate images of individual components, compared to univariate images at long wavelength.