Study of an optical device based on a quasi-phase-matching method for speckle noise reduction for laser display

Abstract

We report on quasi-phase-matched devices design of a red, green and blue (RGB) laser source based on second harmonic generation by using a novel apodized step-chirped grating (ASCG) made from various nonlinear materials. The novel apodized method is achieved by changing the number of segments in each section of the quasi-phase matched devices. The new structures yield extremely large bandwidths of about 5 nm while reducing the spectral ripples. We also demonstrate a broadband green generation by using an ASCG of congruent LiNbO3 and obtain 2 nm spectral bandwidth and 5.6% speckle noise contrast. © 2016, The Korean Physical Society.