Development of holographic methods for low density plasma diagnostics

A holographic setup is described which can be used in tokamak plasma diagnostics, where the product of plasma layer thickness and electron density is about 1014-1015 cm-2. The sensitivity of the interferometric equipment is inversely proportional with the wavelength of the light used, thus the reported setup uses infrared laser radiation, and holographic effects increase the sensitivity. The IR holograms are recorded on a triacetate film, which allows, due to nonlinearity of hologram phase recording, to obtain the reconstructed waves of higher order, up to +-8. (D.Gy.)