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Proceedings Paper

Doppler laser interferometry improvements in detonics
Author(s): Patrick Mercier; Jacqueline Veaux; Jacky Benier; Manuel Vincent; Severine Basseuil
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Paper Abstract

For more than 30 years now, Doppler Laser Interferometry has been used in detonics to measure velocity versus time accurately. The means is composed of: a laser source, an optical fiber bringing light to the moving target, another which collects back-reflected light, a device built around a Fabry-Perot interferometer to create the rings pattern, a streak camera. In the beginning, the source was a CW singlemode argon laser with a 7 W output power. Later, it was replaced by a wide spectrum rhodamine dye laser requiring two twin Fabry-Perot interferometers, the first one modulating the spectrum and the second analyzing the Doppler shifted light; the available power was 1 kW for a 40 μs pulse. Recently, we have improved the means by increasing the channel number with sufficient output power, replacing the dye with a solid amplifier, increasing pulse width, decreasing the velocity and time uncertainties and reducing the volume and the cost of the equipment. To achieve this quality we acquired a long-pulse singlemode Yag laser. It has 15 channels, each providing 1 kW with a 70 μs rectangular pulse at 532 nm. The analysis bench uses only 1 Fabry-Perot interferometer for 5 channels. The laser, target and analysis bench are connected through a 3 optical fibers bundle; one for lighting, one to measure velocity and a third one to record the photometric curve and determine shock breakout time accurately. To improve accuracy, we worked on two areas: (1) the equipment with the anamorphic optical device, the value of the fringe constant and the number of rings lit on the camera slit, (2) the building of a chart where we write all influent parameters in order of importance: in order to decrease the uncertainty of velocities less than 1000 m/s, we need to evaluate the influence of electronic streak camera distortion.

Paper Details

Date Published: 1 August 2003
PDF: 6 pages
Proc. SPIE 4948, 25th International Congress on High-Speed Photography and Photonics, (1 August 2003); doi: 10.1117/12.516947
Show Author Affiliations
Patrick Mercier, Commissariat a l'Energie Atomique (France)
Jacqueline Veaux, Commissariat a l'Energie Atomique (France)
Jacky Benier, Commissariat a l'Energie Atomique (France)
Manuel Vincent, Commissariat a l'Energie Atomique (France)
Severine Basseuil, Commissariat a l'Energie Atomique (France)

Published in SPIE Proceedings Vol. 4948:
25th International Congress on High-Speed Photography and Photonics
Claude Cavailler; Graham P. Haddleton; Manfred Hugenschmidt, Editor(s)

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