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.

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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).

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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).

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