Thermally matched vertical multijunction laser power converters: Design and fabrication for wireless power transmission

Wireless laser power transmission exhibit high directivity and controllability, making them suitable for establishing point-to-point energy transmission networks, particularly in scenarios such as deep space exploration and relay energy supply. To address the practical requirements of space applications, this study focuses on two key aspects: the design of matched structures between subcells and working temperature in large-area GaAs based laser power converter (LPC), and the topology optimization of laser photovoltaic arrays in relation to the incident laser distribution. Specifically, we conducted structural regulation of vertical 6-junction GaAs based LPC under varying temperatures and performed topological design of a novel circularly configured laser photovoltaic array tailored to Gaussian-profile laser illumination. Experimental results demonstrate that the fabricated LPC with a large area of ∼ 13.72 cm 2 achieved a power conversion efficiency of 70.2% under -140 °C. Correspondingly, the large-area circular LPC array achieved a laser-to-electrical conversion efficiency of 50.6% at 25 °C, which, to the best of our knowledge, represents the highest efficiency reported to date for large-area LPC array. Furthermore, a ground-based wireless laser power transmission system over a 50-meter scale was conducted, achieving a maximum electrical-to-electrical conversion efficiency of 16.9%.