The continuous pursuit for emitters with higher power, good beam quality and wavelength tunability has led to the development of devices at the frontier between solid-state and semiconductor laser technologies. Optically-pumped semiconductor disks lasers or vertical-external-cavity surface-emitting lasers (VECSELs), offer many advantages over standard semiconductor lasers such as high brightness, ultra-short pulse generation, single-frequency operation, the use of intracavity elements, and low noise operation. In this regard, devices operating at 1178 nm with intracavity frequency doubling have been shown to provide effective sources for 589 nm light for sodium guidestar laser applications due its low cost, optical simplicity, and wavelength tunability compared to the bulky (>100 Kg) and expensive (> 1M) existing sources. However, the significant long growth time and complexity of the Bragg reflector (DBR), as well as its high thermal resistance, hinder their full exploitation. Recently, DBR-free VECSELs or membrane external-cavity surface-emitting laser (MECSEL) emerged to offer potential solutions to these limitations.

Here, we present the recent achievements and development of new MECSEL platforms in the 1-1.2 µm range using GaInAs MQWs gain structures.

A record 80 nm and 78 nm tuning range centered at 1030 nm and 1160 nm respectively is shown, and attributed to the broader effective gain bandwidth of DBR-free devices, as well as to the low reflectivity at the semiconductor-heatspreader interface, leading to low finesse subcavity and reduced modulation of the gain spectrum.

We also report the highest output power at 1030 nm (16 W) and 1178 nm (13 W) in double-bonded SiC MECSEL using a barrier-pumping scheme (808 nm excitation laser). Moreover, in-well pumping for the 1178 nm MECSEL is investigated to reduce the quantum defect and the subsequent thermal rollover. We attained a differential efficiency of ~52 % adopting a single-pass scheme.  Finally, we propose and analyse an active mirror concept based on a gain-embedded meta-mirror (GEMM). It consists of a broad-band subwavelength grating structure bonded to a heat-dissipating substrate such as diamond or SiC. The thermal analysis on a GaAs-based GEMM-on-diamond structure shows it can outperform traditional VECSELs by more than a factor of 3.  These results show the potential to achieve new optically-pumped semiconductor disk laser wavelengths and the realization of continuous-wave high-power regimes.