Shinichi Shikii

Second Harmonic Generation with High Conversion Efficiency and Wide Temperature Tolerance by Multi-Pass Scheme

We proposed a multi-pass second harmonic generation scheme in which condensed fundamental light passed through a nonlinear crystal many times. The multi-pass scheme was realized by using a wide periodically-poled MgO:LiNbO3, concave mirrors and condensing optics. The total wavelength conversion efficiency of the multi-pass scheme was increased because non-converted fundamental light which had passed through the nonlinear crystal was re-injected and condensed into the nonlinear crystal and converted. Moreover the total temperature tolerance of the multi passes was widened because the fundamental beam passes had different phase-matching temperature and compensated for miss conversions of other passes. In this work, continuous-wave 5 W green light (532 nm) with 66% conversion efficiency and wide temperature tolerance were obtained.

P‐206L: Late‐News Poster: Low Electric Consumption 3.6W Green SHG Laser Light Source Applicable to Laser Projection Systems

Highly-efficient fully air-cooled green laser light source with frequency doubling module is reported. As a result, 3.6 watts green laser light generation with about 9% wall-plug efficiency is achieved. By using fully air-cooled RGB lasers including the green SHG (Second Harmonic Generation) laser and illumination optics for speckle noise reduction, a laser projection engine is prototyped. A laser rear-projection system with this laser projection engine shows several merits; wide color gamut (133%NTSC), 61inch large screen size, and low electric power consumption (less than 100W, at 650cd/m2).