Design Breakthrough Could Spur Advancements in Solar-Pumped Lasers

A team of researchers from Tokai University and Tokyo Motors has developed a fully planar solar-pumped laser. The laser does not require complex light-concentrating systems and is capable of efficiently powering hydrogen fuel generators.

The researchers say the design could herald the widespread adoption of ecofriendly solar-driven lasers to power hydrogen fuel generators, which could potentially power space exploration.

The design relies on a nearly flat cylindrical chamber called a “luminescent solar collector.” The interior of the chamber is highly reflective and contains a solution called “sensitizer.” A coiled kilometer-long laser fiber is submerged in the solution. The top of the chamber is a dichroic mirror through which solar photons pass. The sensitizer then absorbs the photons, reemiting them with a specific frequency through photoluminescence. The photons then excite the laser fiber, collectively producing the required oscillations that generate a laser beam.

The researchers’ first approach yielded unsatisfactory results; the output power of the prototype was too low. In a subsequent study, they improved the design by replacing the previous sensitizer with cesium lead halide perovskite nanocrystals, which they chose because of their advantageous optical properties. By tailoring the composition of the perovskites, the researchers tuned the energy of the photons emitted via photoluminescence to match the optimal level required to excite the laser fiber.

The research was published in the Journal of Applied Physics (www.doi.org/10.1063/5.0011945).