New Concept of Compact Optical Fourier-Transform Spectrometer

Here is presented a concept of a compact optical Fourier-transform spectrometer (FT) working in a wide spectral range in real time and containing no moving parts. Most of the existing FT spectrometers consist of optics to create an image of the interference pattern on the detector plane. The concept presented here does not require these optical components because interferometer consists of multi channel Fabry Perot interferometer with stepped or gradually changing thickness attached directly to the detector array or detector matrix. As a result this allows complete integration of the interferometer with the detector together to one of the main spectrometer units. Two types of these spectrometers were simulated and experimentally tested. The first type with the wedge interferometer is suitable for analysis of optical radiation with partially coherent radiation and exhibits higher resolution and response to coherent radiation and lower response for non coherent radiation. Second one with cylindrically shaped interferometer suitable for spectroscopy with white sources shows lower spectral resolution. Both types of the spectrometers were tested from 0.6 mum to 2 mum with a 256 pixels extended InGaAs array detector.