Power-scaled CW Alexandrite lasers

Abstract

We present several strategies for increasing the output laser power of near-diffraction limited continuous-wave Alexandrite lasers pumped by fibre-coupled red laser diodes. Laser mode size control using a convex mirror with the varying thermal lens is shown to be an efficient method for generating record levels of output power from a diode-pumped Alexandrite laser. 8.6 W is obtained with $$M^{2}<1.1$$ M 2 < 1.1 and an optical efficiency of 27%. 735–790 nm wavelength tuning is demonstrated with $$> {2.5}\,\hbox {W}$$ > 2.5 W and a record dual-wavelength output power of 4.2 W. In a ring-cavity geometry, 5.1 W is obtained with $$M^{2}<1.1$$ M 2 < 1.1 showing promising potential for multi-watt single-longitudinal-mode operation. Detailed laser cavity modelling including thermal lens analysis is also provided.

375-400nm SHG Alexandrite laser using Zn-indiffused MgO:PPLN ridge waveguides

“…Diode-pumped Alexandrite (Cr:BeAl 2 O 4 ) lasers have emerged as a highly versatile laser source in the near infrared at around 720-820 nm. 1 Second-harmonic-generation (SHG) in periodically-poled lithium-niobate (PPLN) waveguides is an efficient way of generating multi-watt level of output power from continuous-wave lasers. Znindiffused MgO-doped PPLN waveguides have recently emerged as a scalable approach for generating highefficiency watt-level visible laser output.…”