A Fabry-Perot Interferometer With A Spatially Variable Resonance Gap Employed As A Fourier Transform Spectrometer

We demonstrate a Fourier transform spectrometer (FTS) using a Fabry-Perot interferometer with the gap between its partially reflecting layers varying orthogonal to the optical axis to produce a gradient in optical path difference at a detector. The gradient produces a period fringe pattern that can be analyzed with standard FTS techniques. Experiments in the visible and IR demonstrate the feasibility of this method for spectroscopy.