# Over 1.65 GW cm−2 sr−1 brightness 590 nm yellow second-harmonic generation in MOCVD-grown high-strain InGaAs/GaAs quantum well VECSEL

## TL;DR

This paper presents a high-brightness yellow laser using MOCVD-grown InGaAs quantum wells, achieving record performance for applications like atomic cooling and optogenetics.

## Contribution

The study introduces a novel MOCVD growth strategy for high-strain InGaAs quantum wells, enabling efficient yellow second-harmonic generation with exceptional brightness.

## Key findings

- MOCVD-grown gain chips produced over 45 W output power with >50% slope efficiency.
- Yellow SHG achieved 6.2 W at 590 nm with 17% slope efficiency and near-diffraction-limited beam quality.
- Brightness of ~1.65 GW cm−2 sr−1 was attained, the highest reported for yellow lasers.

## Abstract

High-brightness yellow lasers are in high demand for applications such as atomic cooling and trapping, optogenetics, and sodium laser guide stars. Herein, we demonstrate the potential of Metal-Organic Chemical Vapor Deposition (MOCVD) for the rapid mass production of high-strain 1.2 μm InGaAs quantum well vertical external cavity surface emitting lasers (VECSELs). Two distinct growth strategies were explored, with a primary focus on enhancing crystal thermal stability and mitigating indium segregation. The as-grown gain chips achieved over 45 W of output power and a slope efficiency exceeding 50%. Furthermore, we verified the feasibility of generating yellow second harmonic generation (SHG), attaining a 590 nm CW power of ~6.2 W with a slope efficiency of 17%. The beam quality factor (M²) was <1.1, approaching diffraction-limited performance, corresponding to a brightness of ~1.65 GW cm−2 sr−1. Overall, these investigations not only expand the performance envelope of MOCVD-grown semiconductor lasers but also deepen the understanding of indium segregation behaviors.