Abstract

Laser diode pumped solid-state lasers with high TEM₀₀-mode conversion efficiencies have been demonstrated using both end-pumped¹ and side-pumped² geometries. However, side-pumped systems obtain their TEM₀₀-mode quality through the use of pumping geometries that require tens of laser diode bars. Given the high cost of quasi-cw laser diodes, side-pumped lasers operating at the tens of millijoule level are cost effective only when pumped by as few laser diode bars as possible. Single-array (up to five bars) pump sources in side-pumped geometries³-⁵ have been unable to demonstrate efficient TEM₀₀-mode operation. We describe a self-imaging side-pumped geometry with efficient TEM₀₀-mode conversion using a single, five-bar, quasi-cw laser diode array as the pump source. We have demonstrated 23% slope efficiency and 11.8 mJ energy at 1064 nm for 64 mJ cf pump energy at 808 nm. This approach should allow efficient generation of TEM₀₀-mode quality beams at energies up to several tens of millijoules, beyond which radially pumped rod² geometries become more effective.

© 1991 Optical Society of America