Design and Development of a High-Performance LED-Side-Pumped Nd:YAG Rod Laser

We present a design and development of a high-performance light-emitting diode (LED)-side-pumped Nd:YAG rod laser with strong pulse energy, high efficiency, and consistency, very good beam quality, and high uniform pumping intensity in the active area which reduces the effects of thermal gradient significantly. A five-dimensional 810 nm LED array with a full width of 30 nm at half maximum was intended to achieve high coupling efficiency by putting the LED array as close as possible to the side of the Nd:YAG laser rod for overcoming the large pumped divergence. Under 2.25 J pump energy, maximum single pulse energy of 35.86 mJ with duration of 1.24 µs at 1063.68 nm was obtained, equivalent to optical efficiency of 1.59% and a slope efficiency of 2.53%. The laser was set to repeat at a rate of 10 Hz with a beam quality factor of M_x^2 = 2.94 and M_y^2 = 3.35, as well as with the output power stability of <  4.1% (root mean square) and <  7.3% (peak to peak). To the best of our ability, this is the highest performance for an LED-side-pumped Nd:YAG rod laser oscillator with a 10-mJ-level output ever reported.