1064 nm solar laser achieves record power output and efficiency
Solar-pumped lasers have improved in performance again, thanks to research conducted at the New University of Lisbon.
With applications in remote sensing from space, wireless laser power beaming, asteroid deflection, and fuel-free photonic thrusters, lasers that emit energy directly through the conversion of sunlight—called solar-pumped lasers—have improved in performance again, thanks to research conducted at the New University of Lisbon (Lisbon, Portugal).
Unlike other architectures that transported laser energy from a solar tracking system via an optical fiber with moderate loss, the Lisbon researchers instead used end-side-pumping of a 4.0-mm-diameter, 35-mm-long neodymium:yttrium aluminum garnet (Nd:YAG) single-crystal rod with a heliostat-parabolic-mirror solar energy concentration system. An aspheric fused-silica lens coupled concentrated solar energy from a 1.4-m-effective-diameter parabolic mirror into the laser rod within a conical pumping cavity, producing 37.2 W of continuous-wave (CW) multimode 1064 nm solar laser power with 8.9% slope efficiency—the highest solar-laser efficiency to date, according to the researchers. In addition, 9.3 W of CW TEM00-mode (m2 ≤1.2) 1064 nm solar laser power was also measured, resulting in a 7.9 W/m2 fundamental-mode laser collection efficiency that is 2.6X and 2.0X higher than the previous Fresnel lens and parabolic mirror records, respectively. Reference: D. Liang et al., Sol. Energ. Mat. Sol. Cells, 159, 435–439 (Jan. 2017).