Abstract: The present invention provides a polarizing interferometer multiplex spectrometer using a zero-order switch, a multi-order switch and an output polarizer to multiplex the recovery of an entire input spectrum. The zero-order switch and multi-order switch require input light of a fixed polarization; thus the present invention provides a preferred embodiment that uses a zero-order switch and a multi-order switch positioned between an input polarizer and an output polarizer. For a sequence of time delays incremented by the multi-order and zero-order switches, the total transmitted power at all wavelengths is measured. From these, the coefficients of a Fourier series representation of the input spectrum are obtained, and the entire spectrum is mathematically reconstructed. Although the structure is similar to a tunable interference filter, the PIMS does not function as a filter, and more particularly, does not scan the transmission wavelength and measure power as a function of wavelength.

Abstract: A chopper has a straight knife clamped between a clamping member and a counter knife. The knife, clamping member, and counter knife are collectively positioned in a machined area formed in a holder that is in turn fitted within a larger recess formed in a chopping disk. A first fastener secures the knife holder to the chopping disk, a second fastener secures the clamping member to the knife holder, and a third fastener secures the counter knife to the knife holder. A projection formed in the counter knife engages a groove formed in the knife to properly align the knife and to inhibit entry of fibers into the space between the counter knife and the knife. The holder further includes a series of steps that position the counter knife and the clamping member, respectively, with respect to the holder.

Abstract: This invention provides a multipass Solc filter which utilizes liquid crystal variable retarders to provide high resolution and tunability. The Solc polarization-interference effects are used synergistically with the Fabry-Perot cavity resonances. The cavity comprises a central retarder, two quarter wave plates, and an optional isotropic spacer. The central retarder or the isotropic spacer can include liquid crystal cells to provide tuning of the Solc envelope or the cavity resonances respectively. In one embodiment the variable retarder is a three element quarter-half-quarter device with a liquid crystal electro-optically rotatable half-wave plate. Reflection mode configurations are introduced wherein, because of the bilateral symmetry of the Solc filter, it is possible to use only half of the intracavity elements. Criteria for designing filter parameters to meet resolution, out-of-band discrimination, and tuning range requirements are provided.