Modulation and efficiency characteristics of miniature microchip green laser sources based on PPMgOLN nonlinear material

Abstract

We report on highly efficient diode-pumped solid-state (DPSS) green laser source based on a monolithic cavity microchip laser platform. The use of periodically poled MgO-doped Lithium Niobate (PPMgOLN) as the nonlinear frequency doubler together with gain material Nd³⁺:YVO₄ allows obtaining a significant increase in the overall efficiency of green microchip laser in comparison with other compact green laser source architectures with comparable output power. We discuss our progress in miniaturization and efficient operation across a wide range of temperatures and application-specific modulation conditions. In particular, we demonstrate 50mW-120mW average green output power (30% duty cycle) with wall-plug efficiency over 13%. Efficient laser operation with duty cycle ranging from 10% to 60% in a wide range of repetition rates is also demonstrated. The laser is designed to be a part of the miniature and efficient RGB light source for microdisplay-based (LCOS, DLP or similar) mobile projector devices. While these projection architectures typically require modulation rates from 60Hz to about 2000Hz depending on design, we extended modulation speed up to 2MHz that can be of interest for other applications. A very efficient and small microchip as well as alignment-free design allow us to package this laser source into the very small volume of only 0.23cm3 (bounding box). We present results of performance tests for this packaged laser and demonstrate that such a miniature package can support laser operation with average power output of over 250mW.