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Instrument: FOURIER TRANSFORM SPECTROMETERS |
Related Data Sets View all records related to this instrument Description A Fourier transform spectrometer (abbreviated FTS) is a Michelson interferometer with a movable mirror. By scanning the movable mirror over some distance, an interference pattern is produced that encodes the spectrum of the source (in fact, it turns out to be its Fourier transform ). Fourier transform spectrometers have a multiplex advantage over dispersive spectral detection techniques for signal, but a multiplex disadvantage for noise. In its simplest form, a Fourier transform spectrometer consists of two mirrors located at a right angle to each other and oriented perpendicularly, with a beamsplitter placed at the vertex of the right angle and oriented at a 45? angle relative to the two mirrors. Radiation incident on the beamsplitter from one of the two "ports" is then divided into two parts, each of which propagates down one of the two arms and is reflected off one of the mirrors. The two beams are then recombined and transmitted out the other port. When the position of one mirror is continuously varied along the axis of the corresponding arm, an interference pattern is swept out as the two phase-shifted beams interfere with each other. Additional information available at "http://scienceworld.wolfram.com/physics/FourierTransformSpectrometer. html" [Summary provided by Science World] |