Laser speckle reduction based on angular diversity induced by piezoelectric benders

Abstract

Speckle reduction techniques have been investigated in display systems with coherent light sources. We propose a simple but efficient method to reduce speckle via two fast vibrating piezoelectric benders. The concept is modulating laser beams to have angle diversity and reducing speckle by temporal averaging in the integration time of the detector. Experiments demonstrate that the speckle contrast is suppressed down to 0.06. Both free space and imaging geometry are considered. In order to fairly evaluate the speckle reduction, the optical configuration as well as the camera settings, which largely affect the speckle contrast, is discussed.