Study On Thermal Management Of Optically Pumped External Cavity Surface Emitting Laser

Optically pumped vertical external cavity surface emitting laser light can output TEM00 mode, which combines the advantages of semiconductor lasers and surface pumped solid state lasers emit light, high power, high beam quality and can easily be clamping and cavity frequency doubling, are widely used in laser display a new field of laser light, forensic medicine and biotechnology instrumentation field.This paper describes the development of semiconductor lasers. Comparing with solid-state lasers and gas lasers resulting that semiconductor lasers can be directly pumped by a current or optical pumping. OP-VECSEL evolved from the semiconductor laser pumped solid-state lasers.Describes the advantages of OP-VECSEL: optically pumped vertical external cavity surface emitting laser no p-n junction, no electrical contact, simplifying the growth process of the laser chip, do not need such as lithography and etching mesa extra treatment, can flexibly adjust the cavity length, so that optically pumped vertical external cavity surface emitting laser output wave length can cover from the infrared to visible light. Band gap engineering allows to optimize vertical external cavity surface emitting laser pump power distribution, in order to eliminate the multiple quantum carrier transport limitations and optimization of the barrier, can maximize pump absorption efficiency and limitations of quantum wells carriers thereby minimizing unnecessary heat generated due to optical pumping. Referred to the vertical external cavity surface emitting lasers are widely used alternative to the use of traditional devices in a number of areas. But it also refers to a vertical external cavity surface emitting laser epitaxial wafers in the growth process due to equipment and other causes of non-uniformity, will change the length of the semiconductor microcavities, when the active region of the temperature rise, the laser output wavelength will red shift. Most applications require wavelength stability and width requirements, these shortcomings may limit the optically pumped vertical external cavity surface emitting laser applications in these areas.Describes the optically OP-VECSEL basic theory and structure of epitaxial wafers,epitaxial wafers are given a structure operating principle schematic energy band gap,vividly illustrates the formation mechanism of the laser. Describes the design principles and the epitaxial film distributed Bragg reflector derivation formula,discussed the relationship between the reflectivity and the number of parity period film,obtained reflectivity number of even-odd layer membrane layer is larger than the number of films. Introduces the multi-quantum well active region due to lattice mismatch stress caused by defects and dislocation strain theory of quantum wells, and the critical thickness of the quantum well and did a calculation of the spontaneous emission spectra were analyzed. Gives the light distribution in the optical field of the periodic gain structure. According to the experimental data plotted threshold relationship between carrier power, the threshold pump power and the number of quantum wells. Distributed Bragg reflector on the size of the spot, the relationship between the spot and the cavity length mirror on the outside of the graph shows the relationship.Describes the basic idea of thermal management of OP-VECSEL and the establishment and analyzed the bottom of the radiator and window heat sink thermal model, the actual results of the radiator shape has little effect on the results, from all around the bottom of the heat and the heat only from changes in temperature within the range of a few percent, given the thermal conductivity of several materials used.Describes the common methods of thermal management for optically pumped vertical external cavity surface emitting laser, including the use of thermal window pieces, wafer substrate removal. Gives the wafer structure and composition tables, so better targeted removal of the matrix, which includes the removal of the wafer substrate mechanical thinning method to remove most of the matrix and then use chemical etching to remove the rest of the matrix, or removal of the direct use of chemical etching.