Citation:
Kissinger, T., Charrett, T.O.H., James, S.W., Adams, A., Twin, A. and Tatam, R.P. 2015. Simultaneous laser vibrometry on multiple surfaces with a single beam system using range-resolved interferometry. Proceedings of the SPIE, 9525, Optical measurement systems for industrial inspection IX, paper number 952520. DOI: 10.1117/12.2183281
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 inside. This allows the separation of common-mode vibrations of the whole cryostat from differential vibrations between the window and the sample holder.
