Improving the efficiency of high-power diode lasers using diamond heat sinks

Abstract

Using multifunctional ion beam and magnetron sputtering systems, we have developed chemical and vacuum techniques for producing metallic coatings firmly adherent to various surfaces, with application to copper and diamond heat sinks for diode lasers. Conditions have been optimised for mounting diode lasers and bars using the proposed metallisation processes, and significant improvements in the output parameters of the devices have been achieved. The power output of cw laser diodes on diamond heat sinks increases by up to a factor of 2, the linear (working) portion of their power-current characteristic becomes markedly broader, and their slope efficiency increases by a factor of 1.5 — 2 relative to that of lasers on copper heat spreaders. The use of diamond heat sinks extends the drive current range of pulsed diode bars by a factor of 2 — 3 and enables them to operate at more than one order of magnitude longer pump pulse durations (up to milliseconds) when the pulse repetition rate is at least 10 Hz.