Eye-safe 1.5 µm passively Q-switched solid-state Raman laser

Due to the low output energy of the passively Q-switched laser, a challenge is to achieve an efficient stimulated Raman generation via a passively Q-switched laser pumping strategy, especially the generation of a Raman laser at 1.5 µm. In this paper, the first-order Raman laser at 1525 nm was successfully demonstrated through a passively Q-switched Nd:YVO₄/V:YAG excitation with a compact and an easily integrable structure. The pulse energy at 1525 nm could be up to 17.6 µJ at 1 kHz repetition rate with a pulse duration of 6.2 ns. The corresponding optical efficiency was 23%, and the measured beam quality factor M² < 1.3. Raman lasers operating at 1.5 µm have important applications in fields such as optical communication, laser scanning, distance measurement, remote sensing, and spectral analysis.