Post Processing And Spectral Characteristics Of InGaAs Quantum Wells Semiconductor Disk Laser

Semiconductor disk lasers combine advantages of surface-emitting lasers,edge-emitting lasers and diode-pumped solid-state lasers, can produce good quality beam with diffraction-limited fundamental transvers mode and high output power simultaneously. By the use of band engineering, emitting wavelengths of semiconductor disk lasers have coverage from visible to near infrared. The high intra-cavity circulating power support intra-cavity frequency doubling and mode locking, make it very useful in laser display, biomedical sciences and optical communication system.This thesis reviews the background and research significance of semiconductor disk lasers, summaries its advantage and introduces the recent advances of mode-locked and frequency-doubled semiconductor disk lasers. In the section of basic knowledge,two different structures of gain chip used in InGaAs quantum wells semiconductor disk laser are described, and the corresponding post processing are introduced. Using the band theory, based on a designed structure of gain chip of a 980 nm semiconductor disk laser, the influences of strain on the band structures and the critical thickness of quantum wells with different materials are discussed, and structure parameters of quantum wells in a 980 nm semiconductor disk laser are calculated theoretically. To analyze the reflectivity and the band width of the distributed Bragg reflector,mathematic equations are employed through the interference theory and transmission matrix of multiple beams, and the layer thicknesses of the reflector are simulated.The fundamental theory of thermal management in semiconductor disk lasers is introduced, and the post processing of gain chip, which is grown up-side-down, is determined. After the theoretical analysis of the capillary bonding, the cleaning steps of gain chip and SiC heatspreader are given, and a gain chip and a SiC heatspreader are capillary bonded successfully under the use of a home-made pressurizing device.Researches of surface metallization and In soldering technology of the gain chip are carried out, and the substrate of a gain chip is etched smoothly. Some problems of post processing are discussed and proper solutions are given.The spontaneous emission spectrum and the reflection spectrum of a gain chip are studied experimentally, the edge-emitting and surface-emitting spectrum under differentheatsink temperature are measured. Through analyzing the characteristics of spontaneous emission spectra, gain structures of semiconductor disk lasers can be optimized, and this provide basic support of a high power and good beam quality semiconductor disk laser.