Application of speckling for measuring the deflection of laser light by phase objects

doi:10.1016/0030-4018(72)90030-2

Optics Communications

Volume 5, Issue 5, August 1972, Pages 347-350

https://doi.org/10.1016/0030-4018(72)90030-2 Get rights and content

Abstract

The image of a coherently illuminated diffusor exhibits a characteristic speckle pattern which changes when a phase object is interposed in the path of the beam. If the image is formed by only thin pencil beams, the deflection of each pencil by a low-refractive phase object can be determined from the local displacement of the speckle pattern by means of a photographic double-exposure Fourier technique. Such displacements are measured to determine density and temperature distributions in axial-symmetric gaseous phase objects.

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The change of the deflection angle can be regarded as a local translation of the artificial speckle pattern. In strict analogy with traditional speckle photography [6–9], this speckle displacement is proportional to the temperature gradient. Therefore, in WLSP temperature (density) gradient fields can be measured.
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Application of speckling for measuring the deflection of laser light by phase objects

Abstract

Laser und angewandte Strahlentechnik

Opt. Commun.

Opt. Acta