Cryogenic fibre-fed laser metrology

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Christiansen, Adam J.
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Lethbridge, Alta. : University of Lethbridge, Department of Physics and Astronomy
Cryogenic cooling is a fundamental requirement for broadband far-infrared spectroscopic instrumentation to benefit from state-of-the-art far-infrared detectors. The precision to which the moving cryogenic components of the instrument can be measured and controlled affects its ability to recover the spectrum and exacts a low power robust position metrology system. This thesis explores a number of laser-based position metrology solutions and shows that a fibre-fed range-resolved interferometer meets the stringent precision and low power requirements of a metrology system for future space missions. Two cryogenic fibre-fed range-resoled interferometers are theoretically discussed and subsequently constructed; the first using the Clarke transform to decode three-phase signals, and the second based on sinusoidal laser frequency modulation. Experimental results of room and cryogenic (<4 K) temperature testing for both systems are presented. Lessons learned, suggested improvements, and the employment of a range-resolved interferometer for cryogenic accelerometry, lunar seismology, and other applications are discussed.
Cryogenic , Electronics , Interferometry , Laser , Metrology , Photonics , Position metrology , Range-resolved interferometry , Signal processing , Cryoelectronics , Interferometers , Electronic apparatus and appliances -- Thermal properties , Electronic apparatus and appliances -- Temperature control , Materials -- Effect of space environment on , Low temperature engineering , Laser interferometers , Dissertations, Academic