Mercury cadmium telluride focal-plane array detection for mid-infrared Fourier-transform spectroscopic imaging

By combining step-scan Fourier-transform Michelson interferometry, an infrared microscope, and mercury cadmium telluride focal-plane array image detection we have constructed a mid-infrared spectroscopic imaging system that simultaneously records high-fidelity images and spectra of materials from 3500 to 900 ${\mathrm{cm}}^{-1}$ (2.8 to 11 $\mathit{\mu }\mathrm{m}$) at a variety of spectral resolutions. The fidelity of the spectral images is determined by the pixel number density of the focal-plane array. Step-scan imaging principles and instrument design details are outlined. Spatial resolution measurements and infrared chemical imaging examples are presented, and the results are discussed with respect to implications for chemical analysis of biosystems and composite materials.