Increased Conversion Efficiency at 800 W Continuous Wave Output From Single 1-cm Diode Laser Bars at 940 nm

Diode lasers are key sources of optical energy for industrial machine tools and continuous improvement in their performance is needed to support performance and cost scaling efforts. For example, disk lasers as used in laser tools for metal cutting are typically pumped in continuous wave (CW) mode by 1-cm wide diode laser bars with an operating wavelength around λ = 940 nm, and ongoing increases in optical power per bar P opt are needed. Specifically, power scaling is needed above the current CW commercial level of around P opt = 300 W per bar [1] . Bars with performance at P opt = 1 kW and above have been demonstrated in research studies for many years (e.g. [2] ), with most work focussing on bar optimization for pulsed operation (ns-ms) as recently reviewed in [3] .