Spectroscopic imaging with uncooled microbolometer camera and step-scan FTIR

Abstract

The purpose of this thesis research was to explore the feasibility of spectral imaging using a microbolometer infrared camera and a step-scan Fourier transform infrared spectrometer (FTIR). Spectral imaging is usually carried out using cryogenically cooled semiconductor based focal plane arrays (FPAs) which provide higher sensitivity compared to microbolometer FPAs based on thermal sensors. The key advantage of spectral imaging is the ability to extract spatial variations of spectral information. During the measurement, images were collected as the moving mirror of the FTIR stepped across the zero crossings of the on-axis portion of the interferogram. The preliminary data indicate that interferograms can be successfully recorded using the microbolometer camera, and that data from individual pixels of the camera showed the expected intensity profile. The interferograms from the individual pixels were inverse Fourier transformed to recover the intensity of the broadband infrared source of the FTIR at different pixels. The initial data showed relatively low signal to noise ratio indicating that signal averaging is necessary at each mirror step by collecting several images as well as optimizing the image collecting optics.