Diode-pumped laser with a strong thermal lens effect

摘要

A high power, highly efficient laser that produces a polarized, round diffraction limited gaussian beam is disclosed. A strong thermal lens laser crystal (24) with controlled ellipticity, is mounted in a laserhead (10) and pumped by a fiber-bundle-coupled (22) diode source (18). The pump beam diameter in the crystal is greater than the crystal's TEM00 mode diameter. The laser operates well over a large range of pump powers. Its slope efficiency in the TEM00 mode is greater than 40 %, with an overall efficiency greater than 25 %. One of the lasing crystals used is Nd:YVO4. This material exhibits high gain and a short upper state lifetime. These properties make it attractive in designing a Q-switched laser, or one that is insensitive to optical feedback.