Application of holographic interferometry for plasma diagnostics

The principle of holographic interferometry is described and its importance for plasma diagnostics is indicated, particularly for the determination of electron concentration (Section 2). A review is given of different methods for increasing the sensitivity associated with penetration into the infrared region of the spectrum, and also with the use of multiple-pass, resonance, dispersive nonlinear and two-wavelength holographic interferometry. Section 3 discusses the experimental techniques–recording media and radiation sources–as well as the results of fringe shift measurements, stroboscopic holography and cineholography. Section 4 gives a review of work on investigation of various plasmas–laser-induced sparks, laser jets, neutral current layers, $z$- and $\theta$-pinches, flash lamps, CO$_2$ laser-induced plasmas, exploding conductors, plasmotrons, electric arcs and various other kinds of electric discharges in gases.