17 March 2005 Velocimetry using heterodyne techniques
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Proceedings Volume 5580, 26th International Congress on High-Speed Photography and Photonics; (2005) https://doi.org/10.1117/12.567579
Event: 26th International Congress on High-Speed Photography and Photonics, 2004, Alexandria, Virginia, United States
At LLNL, we have been using heterodyne techniques for the past year and a half to measure velocities up to several kilometers-per-second on different types of experiments. We assembled this diagnostic, which we call the Heterodyne Velocimeter (HetV), using commercially available products developed for the communications industry. We use a 1550 nm fiber laser and single mode fibers to deliver light to and from the target. The return Doppler-shifted light is mixed with the original laser light to generate a beat frequency proportional to the velocity. At a velocity of 1000 m/s, the beat signal has a frequency of 1.29 GHz. We record the beat signals directly onto fast digitizers. The maximum velocity is limited by the bandwidth of the electronics and the sampling rate of the digitizers. The record length is limited by the amount of memory contained in the digitizers. This paper describes our approach to measuring velocities with this technique and presents recent data obtained with the HetV.
© (2005) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Oliver Ted Strand, Oliver Ted Strand, Leon Val Berzins, Leon Val Berzins, David R. Goosman, David R. Goosman, William W. Kuhlow, William W. Kuhlow, Paul D. Sargis, Paul D. Sargis, Tony L. Whitworth, Tony L. Whitworth, } "Velocimetry using heterodyne techniques", Proc. SPIE 5580, 26th International Congress on High-Speed Photography and Photonics, (17 March 2005); doi: 10.1117/12.567579; https://doi.org/10.1117/12.567579

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