| DOI | Resolve DOI: https://doi.org/10.1063/1.4807580 |
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| Author | Search for: Razavipour, S. G.; Search for: Dupont, E.1; Search for: Fathololoumi, S.1; Search for: Chan, C. W. I.; Search for: Lindskog, M.; Search for: Wasilewski, Z. R.1; Search for: Aers, G.2; Search for: Laframboise, S. R.1; Search for: Wacker, A.; Search for: Hu, Q.; Search for: Ban, D.; Search for: Liu, H. C. |
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| Affiliation | - National Research Council of Canada. Information and Communication Technologies
- National Research Council of Canada. Security and Disruptive Technologies
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| Format | Text, Article |
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| Subject | Coupling strengths; Fabricated device; Injection currents; Metal-metal waveguides; Non-equilibrium Green's function; Oscillator strengths; Population inversions; Terahertz quantum-cascade lasers; Gallium arsenide; Gold; Semiconducting gallium; Quantum cascade lasers |
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| Abstract | We designed and demonstrated a terahertz quantum cascade laser based on indirect pump injection to the upper lasing state and phonon scattering extraction from the lower lasing state. By employing a rate equation formalism and a genetic algorithm, an optimized active region design with four-well GaAs / Al0.25 Ga0.75 As cascade module was obtained and epitaxially grown. A figure of merit which is defined as the ratio of modal gain versus injection current was maximized at 150 K. A fabricated device with a Au metal-metal waveguide and a top n+ GaAs contact layer lased at 2.4 THz up to 128.5 K, while another one without the top n+ GaAs lased up to 152.5 K (1.3ω/kB). The experimental results have been analyzed with rate equation and nonequilibrium Green's function models. A high population inversion is achieved at high temperature using a small oscillator strength of 0.28, while its combination with the low injection coupling strength of 0.85 meV results in a low current. The carefully engineered wavefunctions enhance the quantum efficiency of the device and therefore improve the output optical power even with an unusually low injection coupling strength. |
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| Publication date | 2013-05-29 |
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| In | |
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| Language | English |
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| Peer reviewed | Yes |
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| NPARC number | 21270464 |
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| Export citation | Export as RIS |
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| Report a correction | Report a correction (opens in a new tab) |
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| Record identifier | 8241dee6-ff57-401f-9626-fe7fcbd7ffc7 |
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| Record created | 2014-02-12 |
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| Record modified | 2020-04-22 |
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