An LED-pumped 3-mJ TEM 00 Q-switched Nd:YLF laser

We report, to the best of our knowledge, the first direct pumping of a millijoule-level Nd:YLF solid-state laser with high-power light-emitting diodes (LEDs), motivated by the demand for scalable, efficient, and cost-effective laser drivers for inertial confinement fusion (ICF). A Nd:YLF rod laser was constructed using 140 infrared LEDs arranged in a symmetric four-sided pumping geometry. The system was operated in cavity-dumped Q-switched mode, yielding pulse energies of 3.6 mJ while maintaining near-diffraction-limited TEM 00 operation with beam quality factors of M 2 = 1.08 and 1.15 and a pulse duration of 13.8 ns. The Findlay–Clay analysis revealed a single-pass gain of 1.223 ± 0.001 without indication of saturation of the gain at the applied pump levels, indicating further scaling potential through increased pump radiance and optimized coupling. Long-term stability measurements demonstrated robust operation at 0.5 Hz over more than 380 minutes with pulse-to-pulse fluctuations of 2.3 %, while thermal effects limited operation at 1 Hz.