Simultaneous emission of four TEM ₀₀ -mode solar-pumped lasers

The improvement of <i>T</i><i>E</i><i>M</i>₀₀-mode laser conditions is a key focus in solar laser research, especially for applications requiring low divergence and high power density. Using multiple active media to mitigate thermal load is a promising strategy to enhance beam quality, scalability, and stability of laser output power. However, to our knowledge, no experimental research has been conducted on the emission of multiple <i>T</i><i>E</i><i>M</i>₀₀-mode solar laser beams. This paper reports, to the best of our knowledge, the first simultaneous emission of four <i>T</i><i>E</i><i>M</i>₀₀-mode solar laser beams, utilizing a heliostat-parabolic mirror system of PROMES-CNRS, alongside a laser head composed of an aspheric lens, a conical pump cavity, and four Ce:Nd:YAG rods in an end-side pump configuration. A total <i>T</i><i>E</i><i>M</i>₀₀-mode laser power of 6.05 W was achieved, corresponding to an 8.77<i>W</i>/<i>m</i>² collection efficiency and a 0.90% solar-to-laser power conversion efficiency; these efficiencies represent new benchmarks for solar laser systems that incorporate parabolic mirrors, exceeding the previous records, set at the same facility by factors of 1.87 and 1.43, respectively.