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The temporally and spatially modulated Fourier transform imaging spectrometer (TSMFTIS) has the merits of high optical throughput, good mechanical stability, and simple interference configuration. However, the number and the density of pixels in the infrared (IR) focal plane array limit the spectral resolution of TSMFTIS. Thus, we proposed the interferometric supersampling levering multiple sub-pixel translations of the focal plane array detector to realize the supersampling of the interference fringes and improve the system's spectral resolution. The experimental results show that 2.31 cm−1 spectral resolution is achieved by employing a 384×288 uncooled IR detector array. [ABSTRACT FROM AUTHOR]

We present a step height measurement technique using a lateral shearing cyclic path optical configuration (CPOC) setup and polarization phase shifting interferometry (PPSI). In the technique, the CPOC setup generates two orthogonally polarized, laterally sheared, converging beams that get focused at the back focal plane of a positive lens placed at the input beam of the CPOC setup. These focusing beams are reflected back into the CPOC setup by the step optics, positioned in such a way that one of the surfaces of the step optics coincides exactly with the focus point of one of the laterally sheared focusing beams. The CPOC recombines the beams reflected from the step surfaces and the beams re-pass through the lens, which produces collimated and spherical interfering wave fronts for the respective beams. Using PPSI, the radius of the spherical wavefront emerging from the lens, which is related to the focal shift introduced between the reflected beams due to the step height, is determined. The novelty of the technique is the introduction of the CPOC setup and the use of a single wavelength light source to determine the large step height. Results obtained for a step height of 1.340 mm are presented. [ABSTRACT FROM AUTHOR]