Modellierung neuartiger Quantenkaskadenlaser und verwandter Bauelemente für die Terahertz-, Infrarot- und Nachrichtentechnik
Final Report Abstract
The scope of this research project has been to model quantum cascade laser (QCL) structures. The goal was to develop efficient and reliable QCL simulation tools, and apply them to the analysis, optimization and design of THz and mid-infrared QCLs. Based on the semi-classical ensemble Monte Carlo method, we have developed a robust and versatile carrier transport simulator, containing all the scattering mechanisms relevant for the electron transport in the structure. Furthermore, an improved numerical method for solving the Schrödinger-Poisson equation system was devised. One of the major contributions was the inclusion of the laser field into the simulations, enabling us to self-consistently simulate the actual lasing operation and the intrinsic linewidth due to quantum noise. The predicted linewidth of a few 10 Hz for THz QCLs is consistent with recent experimental results. Our simulation tool was validated against various experimental structures, and extensively used for device analysis and optimization. One focus was on the temperature performance of THz QCLs, where we have thoroughly investigated the parasitic channels preventing high temperature operation, and the role of the laser transition diagonality. The obtained insights have been helpful in designing an optimized structure, improving the operating temperature to the current record of 199.5 K for THz QCLs (also featured in Nature Photonics Research Highlights, Nature Photonics 6, 213 (2012)). Furthermore, mid-infrared QCLs have been modeled, with a focus on high-efficiency structures. We were able to reproduce the experimentally obtained wall-plug efficiencies of over 50% in our simulations, and showed that the current transport in such structures is governed by stimulated photon emission and absorption events. Moreover, extensive comparisons to quantum transport simulations have been carried out to clarify the validity range of semiclassical simulations. Good agreement has been found especially in the technically important lasing regime. In addition, also other types of lasers have been modeled. Our work on mode locked and Fourier domain mode locked fiber ring cavity lasers has resulted in an additional DFG-financed project.
Publications
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“Comparative analysis of resonant phonon THz quantum cascade lasers,“ J. Appl. Phys. 101, 086109 (2007)
C. Jirauschek, G. Scarpa, P. Lugli, M. S. Vitiello, and G. Scamarcio
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“Accuracy of transfer matrix approaches for solving the effective mass Schrödinger equation,“ IEEE J. Quantum Electron. 45, 1059– 1067 (2009)
C. Jirauschek
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“Monte-Carlo-based spectral gain analysis for terahertz quantum cascade lasers,“ J. Appl. Phys. 105, 123102 (2009)
C. Jirauschek and P. Lugli
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“Method for security purposes,“ Patent EP2237183-A1; WO2010115775-A1 (2010)
M. Stutzmann, J. Finley, C. Jirauschek, G. Csaba, P. Lugli, E. Biebl, R. Dietmüller, L. Müller, H. Langhuth, and U. Rührmair
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“Modeling bound-to-continuum terahertz quantum cascade lasers: The role of Coulomb interactions,“ J. Appl. Phys. 107, 013104 (2010)
C. Jirauschek, A. Mátyás, and P. Lugli
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“Monte Carlo study of carrier-light coupling in terahertz quantum cascade lasers,“ Appl. Phys. Lett. 96, 011103 (2010)
C. Jirauschek
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“Monte Carlo study of intrinsic linewidths in terahertz quantum cascade lasers,“ Opt. Express 18, 25922 (2010)
C. Jirauschek
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“Temperature performance analysis of terahertz quantum cascade lasers: Vertical versus diagonal designs,” Appl. Phys. Lett. 96, 201110 (2010)
A. Mátyás, M. A. Belkin, P. Lugli, and C. Jirauschek
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“Towards electrical, integrated implementation of SIMPL systems,“ Patent EP2230794-A2; WO2010105993-A2 (2010)
M. Stutzmann, G. Csaba, P. Lugli, J. Finley, C. Jirauschek, C. Jäger, and U. Rührmair
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“Photon-induced carrier transport in high efficiency midinfrared quantum cascade lasers,“ J. Appl. Phys. 110, 013108 (2011)
A. Mátyás, P. Lugli, and C. Jirauschek
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“Improved terahertz quantum cascade laser with variable height barriers,“ J. Appl. Phys. 111, 103106 (2012)
A. Mátyás, R. Chashmahcharagh, I. Kovacs, P. Lugli, K. Vijayraghavan, M. A. Belkin, and C. Jirauschek
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“Terahertz quantum cascade lasers operating up to ~200 K with optimized oscillator strength and improved injection tunneling,“ Opt. Express 20, 3866-3876 (2012)
S. Fathololoumi, E. Dupont, C. W. I. Chan, Z. R. Wasilewski, S. R. Laframboise, D. Ban, A. Mátyás, C. Jirauschek, Q. Hu, and H. C. Liu
