Very efficient speckle contrast reduction realized by moving diffuser device.
Speckle noise reduction is best tested on a precise speckle contrast measurement bench, which should be able to measure 100% contrast in fully developed speckle as well as the smallest contrast (for example, less than 10%) after its reduction. On such a test bench, we have measured very efficient speckle contrast reduction by temporal averaging using a moving diffuser on a tuning fork, which vibrates at 100 Hz over 60 microm in amplitude, a distance that is three times the surface roughness correlation length of the diffuser.
Kubota
Shigeo
S
Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8505, Japan. kubota@iis.u-tokyo.ac.jp
Goodman
Joseph W
JW