Mode-locking of an InAs Quantum Dot Based Vertical External Cavity Surface Emitting Laser Using Atomic Layer Graphene
Final rept. 20 Jan 2012-19 Jan 2015
NEW MEXICO UNIV ALBUQUERQUE
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The InAs quantum dot QD grown on GaAs substrates represents a highly performance active region in the 1 - 1.3mu m wavelength range. The use of such QDs in vertical-cavity devices has resulted in high-power and broad gain bandwidth VECSELs in the NIR. In this project we demonstrate growth and design of InAs QD based VECSELs in the 1200 -1300 nm wavelength range with record CW output powers. We utilize a resonant periodic gain RPG structure with a single QD layer per standing wave antinode to effectively increase the distance between strained layers to improve the quality of the active region. We compare the performance of a VECSEL with 12 separate QD layers 12x1 structure to a more traditional design that uses 4 groups of 3 closely spaced QD layers 4x3. The experimental performance of the 12x1 device is superior to the 4x3 structure in terms of threshold pump power, differential efficiency, and maximum output power. For thermal management, the GaAs wafer of the 12x1 structure was thinned by mechanical polishing, and indium was used to mount the gain mirror on a thermal-grade chemical vapor deposition CVD diamond, allowing for over 6 W of CW output power, which is a record result for stranski-krastanov based quantum dots.
- Lasers and Masers
- Quantum Theory and Relativity