Limits on efficiency and power scaling in semiconductor disk lasers with diamond heatspreaders

Abstract

The semiconductor disk laser (SDL) is a versatile laser source offering multiwatt-level output powers and diffraction limited beams. While an approach to thermal management based on substrate removal has led to tens of watts of output power in the 1 m region, the use of intracavity diamond heatspreaders for thermal management has enabled multiwatt performance levels to be achieved at wavelengths from the red to the midinfrared. The modeling presented indicates that this dichotomy in approach arises from the ability of the heatspreader approach to bypass the thermal resistance of the mirror structure built into the SDL. The power scaling limitations of SDLs with heatspreaders are explored: nonaxial heat flow in the heatspreader is shown to limit the power scaling with pump spot radius. The critical roles of the pump spot size and output coupling on efficiency are experimentally investigated. An output power of 7 W in a 1060 nm SDL is achieved with the maximum output power achieved at a pump spot radius of 85 m

Characterization of Single-Crystal Synthetic Diamond for Multi-Watt Continuous-Wave Raman Lasers

“…Recent developments in chemical vapour deposition growth have led to material with low birefringence and low absorption through the minimisation of the dislocation density and nitrogen impurities respectively [20,21]. This has made the intracavity use of diamond in solid-state lasers more practical -as a heat spreader [28,29] and in Raman lasers [11,[15][16][17][18].…”

Continuous-wave Raman laser pumped within a semiconductor disk laser cavity

“…Second, the losses associated with preferential Raman conversion of lower order transverse modes favor SDL oscillation on higher order transverse modes. Last, small adjustments to the alignment of the pump optics for high-power operation tend to result in a larger pump spot radius favoring operation on higher order transverse modes [13]. However, Raman conversion is typically accompanied by "beam clean-up" [14], and indeed the beam propagation factors of the Raman laser were measured to be M The Raman laser polarization was tilted by ∼15°with respect to the horizontally polarized SDL beam.…”

Tunable narrow linewidth AlGaInP semiconductor disk laser for Sr atom cooling applications

“…This approach, is very efficient for InGaAs based SDLs [21] where the gain structures have a high overall thermal conductivity. In our case, the thermal conductivity of AlGaInP is much lower and the most efficient way to extract the heat is by use of an intracavity heatspreader [22,23]. Another solution consists of using a wedged heatspreader.…”