Principle of FT spectrometer based on a lateral effect position sensitive detector and multi channel Fabry–Perot interferometer

The principle of a new type of multi channel Fourier-Transform spectrometer based on a multi channel wedge Fabry–Perot interferometer using a one dimensional lateral effect Position Sensitive Detector and a scanning slit for interferogram readout have been shown. The design of this spectrometer is very compact and the readout electronics very simple. The drawback of using a scanning slit system is minimized by the use of a position sensitive detector where the position is inherently known for each measurement. Experiments show that the position can be resolved with high accuracy and the summation of the two photocurrents gives the interferogram distribution after scanning the slit between the wedge interferometer and the position sensitive detector. The spectral resolution obtained with a 25 mm wedge interferometer together with a 45 mm position sensitive detector and a 25 μm slit is about 5 nm around 600 nm wavelength range, which is close to the theoretically anticipated resolution. The evaluated spectrometer setup show promising results and could be used in applications where compact and low cost spectrometers are required.