Jaén team reaches 16.3% efficiency with a laser receiver in lab

At 5 W, the nine cells in a receiver built by researchers at the University of Jaén saw radically different amounts of laser light: current stayed below 0.1 A at the edges but reached about 0.45 A in the centre. The team’s solution was a ring-shaped electrical layout, which kept mismatch losses below 3% and brought the module close to its ideal output.

The device is designed for wireless laser power transmission — delivering electricity over distance without a physical connection. It combines a 3 × 3 array of 20 × 20 mm² monocrystalline silicon cells with crossed compound parabolic concentrators, or CCPCs. Made from PMMA, these optical elements redirect incoming light toward the cells and accept illumination across a wider angle.

That optical arrangement also cuts material use. An entrance aperture 2.5 times the cell area enabled a 60% reduction in semiconductor material compared with an equivalent non-concentrated receiver. The complete unit has a frontal aperture of 104 × 104 mm² and a measured mass of 123 g.

Under monochromatic laser illumination around 808 nm, the ring configuration reached close to 16.3% power-conversion efficiency at 806 nm. Series wiring reached 6.9%, while parallel wiring reached 15.2%; the theoretical optimum at 955 nm was 18.4%. The measurements came from the researchers’ laboratory characterization, not from a deployed power system.

So what changes in practice? A receiver like this could make laser power more usable for autonomous systems, remote sensors and aerial platforms where cables or batteries are impractical. It tolerated 30° incidence with maximum power generally remaining at 80–90% of nominal output, but at 45° performance fell substantially once beam displacement exceeded the effective collection area. Alignment, atmospheric losses, conversion efficiency, eye safety and fire safety remain barriers before long-range field use.