| Thermal management has always been one of the core issues that need to be resolved in the development of high-energy lasers.The all-solid-state laser systems are developing towards more efficient heat dissipation.A typical representative is the semiconductorpumped rare-earth-doped disk laser.But the thickness of the disk medium is 100μm order of magnitude,and the heat dissipation limit restricts the available output power in a single disk.Optically pumped semiconductor lasers(OPSLs)have extremely high gain coefficient,allowing the chip thickness to be thinner,usually on the order of μm.By combining carbon-based substrate materials with high thermal conductivity and optical quality,it is expected to realize a new generation of electrically driven and light weight high-energy laser.This paper conducts theoretical and experimental research on carbonbased semiconductor thin film lasers,specifically:1.From the perspective of heat conduction,the paper proposes a way to scale the laser power by expanding the pumping area for thin film gain medium with highly efficient jet impingement cooling scheme.Based on the high hardness,high thermal conductivity and excellent optical quality of carbon-based materials,together with the high gain characteristics of the semiconductor membrane medium,the concept of a new carbon-based high-energy laser was proposed.2.The traditional OPSLs’ theoretical model was improved which could calculate the carrier distribution in individual quantum wells(QWs).Aiming at maximizing the gain,the traditional periodic QW structure was replaced by the non-uniform QW structure,and a front facet reflection structure was proposed to enhance the intra-cavity resonant light intensity.By a synthetically optimization,a new type of OPSL structure with a threshold power density(500W/cm2)that lower than the traditional structure by an order of magnitude was designed.Theoretically,by using the carbon-based substrate combined with the highly efficient jet impingement cooling,the power scaling can be achieved by expanding the pumping area.A single piece of such a laser medium could obtain a highefficiency laser output of more than 20 k W.3.Based on the nationally produced chips,the experimental research of OPSL was carried out.The epitaxial growth,packaging and etching process of the chip were introduced.The performance test of the Ga As/In Ga As semiconductor chip was carried out.By using a 808 nm diode pumping,the 980 nm laser output was successfully demonstrated.The influence of several important parameters was studied.The laser performance under continuous and pulsed pumping conditions were compared to analyze the thermal dissipation characteristics.The pump absorption and the optical conversion efficiencies were studied for comprehensive understanding of the energy distribution channels. |
