High power, high beam quality and narrow linewidth diode-end-pumped Nd:YAG seed laser at 1319 nm for a sodium guide star laser system

Abstract A high power, high beam quality and narrow linewidth Nd:YAG 1319 nm pulsed seed laser for sodium beacon is demonstrated, which was dual-end-pumped by the low quantum loss 885 nm quasi-continuous wave laser diodes (LDs). The resonator was based on a ring convex–convex structure with a dual-rod configuration. Adjusting the effective pump size in the crystal and the temperature of the LDs to realize the optimal size ratio of the pump beam and laser mode was analyzed finely. An output power of up to 25 W at 1319 nm has been obtained, operating at 800 Hz with a pulse duration of 140 μ s, corresponding to a high optical-to-optical conversion efficiency of 18%. The average beam quality factor of M 2 was measured to be 1.25. To the best of our knowledge, this is both the highest output power and the highest beam quality at 1319 nm for the 885 nm LDs end-pumped with the pulse oscillator. This result provides a 1319 nm seed laser for a sodium guide star laser system, with high quality (high power, high beam quality and narrow linewidth), and also better stability.