Speckle reduction by employing two green lasers and two-dimensional vibration of lenses

A method of speckle reduction suitable for use in a laser projector was proposed in the paper. Speckle contrast ratio (SCR) reduction was achieved by combining wavelength diversity and angular diversity methods. First, wavelength diversity was demonstrated by the use of two green laser sources (a 520 nm laser diode (LD) and a 532 nm diode-pumped solid-state (DPSS) laser) at a power ratio of 4:1. Second, angular diversity was achieved via the …