Factors affecting tunable second harmonic generation in a semiconductor disk laser with an intracavity diamond heatspreader

Semiconductor disk lasers have been shown to be a versatile laser technology providing tunable high power operation and good beam quality at wavelengths from 670nm to 2.3pim [1-2]. The addition of a second harmonic generation (SHG) crystal allows this wavelength range to be extended further into the visible, and even into the UV [1]. The limiting factor to the output power of these devices is heating, and two principal techniques have been developed for thermal management. The first is to remove most or all of the substrate, and bond the semiconductor chip to a high thermal conductivity heatsink. The alternative is to use an optical window of high thermal conductivity material bonded to the intracavity surface of the semiconductor chip. Substrate thinning has been very effective in devices around 1 rtm, but at more challenging wavelengths, where the thermal impedance of the semiconductor materials is much greater, the intracavity heatspreader allows heat to be removed over a larger area, improving the efficiency of thermal management (see Figure 1). In order to explore the practicalities of SHG in semiconductor disk lasers with heatspreaders, a test bed system at 1 [tm is used, with the expectation that thermal management and tuning techniques can be transferred to other wavelengths.