Citation:
Thomas Kissinger, Thomas O. H. Charrett, Stephen W. James, Alvin Adams, Andrew Twin and Ralph P. Tatam. Characterisation of a cryostat using simultaneous, single-beam multiple-surface laser vibrometry. 12th International AI VE. LA. Conference on Vibration By Laser and Noncontact Techniques: Advances and Applications, 29th June - 1st July 2016, Ancona, Italy. AIP Conf. Proc. 1740, 100004 (2016)
Abstract:
A novel range-resolved interferometric signal processing technique that uses sinusoidal optical frequency modulation is applied to multi-surface vibrometry, demonstrating simultaneous optical measurements of vibrations on two surfaces using a single, collimated laser beam, with a minimum permissible distance of 3.5 cm between surfaces. The current system, using a cost-effective laser diode and a fibre-coupled, downlead insensitive setup, allows an interferometric fringe rate of up to 180 kHz to be resolved with typical displacement noise levels of 8 pm · Hz−0 5. In this paper, the system is applied to vibrometry measurements of a table-top cryostat, with concurrent measurements of the optical widow and the sample holder target inside. This allows the separation of common-mode vibrations of the whole cryostat from differential vibrations between the window and the target, allowing any resonances to be identified.
