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Experimental investigation of the mixing of two optical frequency EM waves in a plasma

University of British Columbia

The effect of optical mixing of two tunable dye lasers at frequencies near the plasma frequency has been experimentally investigated in a helium plasma jet. It has been shown that the wave mixing produces longitudinal plasma oscillations at the frequency and wave vector of the mixing force. The driven waves were detected by scattering a third diagnostic light wave from their density fluctuation. The scattering signals increased to as much as seven times the signal observed when scattering from the thermal fluctuations alone. The spectrum of the spectral density function of the induced fluctuations has been measured, as well as the dependence of its amplitude on the power of the mixing light beams. These results agree well with theoretical calculations based on a simple model of the mixing effect of a single electron in the field of two electromagnetic waves. The response of the plasma to optical mixing at different frequencies has also been measured. This spectrum agrees in part with theoretical predictions, but has features not explained by the simple model.

Text

2010-02-21

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http://hdl.handle.net/2429/20674

Physics

University of British Columbia

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