Improving 2J In0.20Ga0.80As Laser Power Converters for 1064 nm Power Beaming

Multijunction (MJ) laser power converters (LPC) enable laser power conversion at higher intensity input lasers. Much like solar concentrator photovoltaics, LPCs decrease the current passing through the device and increase the voltage, decreasing the series resistance losses and making the device voltage output more compatible with traditional devices. In our previous work, we created a single junction LPC with an efficiency of 39.8% and a Voc of 0.798 V at 199 mW. Our first round of 2J device results were presented at SPIE Photonics West 2024. Characterization of the metamorphic grade showed good performance, and the high performance of the single junction device was another indicator of a high quality template. Here, we report on the improvement of the two-junction laser power converter for 1064 nm laser light, made of In0.20Ga0.80As metamorphic ally grown on GaAs via metal-organic vapor phase epitaxy (MOVPE). The LPC subcells are curren^tmatched such that each absorbs half of the incident laser light. This reduces the total current relative to a single junction device, enabling the MJ LPC to support higher incident power densities and output more power. The previous 2J device showed room for improvement in efficiency. Here we present our conclusions based on Hovel modeling, as well as our improved two-junction nip LPC and its pin tunnel junction. The applications of these devices include unmanned aerial vehicles (U AV s), lunar rovers, and flexible power-on-demand, line-of-sight, wireless power transmission.