Speckle‐free phase plate (diffuser) for far‐field applications
作者:
S. Skupsky,
T. J. Kessler,
期刊:
Journal of Applied Physics
(AIP Available online 1993)
卷期:
Volume 74,
issue 7
页码: 4310-4316
ISSN:0021-8979
年代: 1993
DOI:10.1063/1.354395
出版商: AIP
数据来源: AIP
摘要:
Phase plates have been used in holography and laser fusion to produce a well‐defined far‐field intensity envelope that is relatively independent of the input‐beam profile. However, superposed on this envelope is unwanted highly modulated speckle from the interference between different phase‐plate elements. The speckle can have deleterious effects such as creating intensities in the nonlinear region of a hologram recording medium or by initiating filamentation and hydrodynamic instabilities in laser‐fusion applications. A technique has been developed for choosing the phase‐plate elements (in combination with polarization rotation) such that these intensity fluctuations approach zero in the limit of plane‐wave near‐field irradiation. For applications where the near‐field phase and amplitude have only small variations, the resulting speckle is also small. Conversely, the observation of far‐field intensity fluctuations can be used to estimate the quality of the near‐field beam.
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