A novel three Ce:Nd:YAG rod solar-pumped laser achieves 4.64% solar-to-laser energy conversion efficiency. A team of researchers led by Dawei Liang, an associate professor at NOVA University of Lisbon in Portugal, are eschewing semiconductor laser arrays and embracing the promise of direct solar pumping of solid-state lasers to overcome current performance limitations and enable reliable operation of spaceborne lasers for years.
Broadband sunlight can be converted into laser light by solar pumping, which can be a source of narrowband, collimated, rapidly pulsed radiation—with the possibility of extremely high brightness and intensity.
“Since solar energy is the most abundantly available and reliable power source in space, 10x more than on Earth, space-based laser power generation would be a major step forward in terms of fulfilling energy needs,” says Liang. “The strength of sunlight in space is nearly twice that of on Earth, and there are 4 or 5x as many hours of sunlight, thanks to the absence of clouds and especially Earth’s night hours.”
Two significant shortcomings of semiconductor laser arrays are performance degradation over time and a limited lifespan—and seem to scale with the level of average output power.
Replacing semiconductor laser arrays with direct solar-pumped solid-state lasers “shows potential to overcome these limitations,” says Liang. “Terrestrial applications may become more obvious if an efficient and cost-effective renewable laser can be operational for laser material processing.”
