Density-matrix theory of the optical dynamics and transport in quantum cascade structures: The role of coherence

The impact of coherence on the nonlinear optical response and stationary transport is studied in quantum cascade laser structures. Nonequilibrium effects such as the pump-probe signals, the spatiotemporally resolved electron density evolution, and the subband population dynamics (Rabi flopping) as well as the stationary current characteristics are investigated within a microscopic density-matrix approach. Focusing on the stationary current and the recently observed gain oscillations, it is found that the inclusion of coherence leads to observable coherent effects in opposite parameter regimes regarding the relation between the level broadening and the tunnel coupling across the main injection barrier. This shows that coherence plays a complementary role in stationary transport and nonlinear optical dynamics in the sense that it leads to measurable effects in opposite regimes. For this reason, a fully coherent consideration of such nonequilibrium structures is necessary to describe the combined optical and transport properties.

[1]  A. Wacker,et al.  Nonequilibrium Green’s function theory for transport and gain properties of quantum cascade structures , 2002 .

[2]  P. Vogl,et al.  Quantum theory of transport and optical gain in quantum cascade lasers , 2008 .

[3]  M. F. Pereira,et al.  Impact of momentum dependent matrix elements on scattering effects in quantum cascade lasers , 2009 .

[4]  P. Lugli,et al.  Limiting Factors for High Temperature Operation of THz Quantum Cascade Lasers , 2007, 2007 Conference on Lasers and Electro-Optics (CLEO).

[5]  A. Knorr,et al.  Occurrence of intersubband polaronic repellons in a two-dimensional electron gas. , 2006, Physical review letters.

[6]  Qing Hu,et al.  Importance of coherence for electron transport in terahertz quantum cascade lasers , 2005 .

[7]  S. Koch,et al.  Quantum-optical spectroscopy of semiconductors , 2006 .

[8]  A. Jauho,et al.  QUANTUM TRANSPORT : THE LINK BETWEEN STANDARD APPROACHES IN SUPERLATTICES , 1997, cond-mat/9711138.

[9]  Koch,et al.  Rabi flopping in semiconductors. , 1994, Physical review letters.

[10]  T. Elsaesser,et al.  Ultrafast coherent electron transport in GaAs/AlGaAs quantum cascade structures , 2002 .

[11]  B. Williams.  Terahertz quantum cascade lasers , 2007, 2008 Asia Optical Fiber Communication & Optoelectronic Exposition & Conference.

[12]  Qing Hu,et al.  Importance of electron-impurity scattering for electron transport in terahertz quantum-cascade lasers , 2004 .

[13]  C. Sirtori,et al.  Ultrafast coherent electron transport in semiconductor quantum cascade structures. , 2002, Physical review letters.

[14]  Thomas Elsaesser,et al.  Coherent charge transport in semiconductor quantum cascade structures , 2004 .

[15]  Andreas Wacker,et al.  Temperature dependence of the gain profile for terahertz quantum cascade lasers , 2007, 0711.2645.

[16]  F. Capasso,et al.  Recent progress in quantum cascade lasers and applications , 2001 .

[17]  Qing Hu,et al.  Continuous-wave operation of terahertz quantum-cascade lasers above liquid-nitrogen temperature , 2004 .

[18]  Marcella Giovannini,et al.  Gain recovery dynamics and photon-driven transport in quantum cascade lasers. , 2008, Physical review letters.

[19]  Francesco Petruccione,et al.  The Theory of Open Quantum Systems , 2002 .

[20]  Kuhn,et al.  Electron-phonon quantum kinetics in pulse-excited semiconductors: Memory and renormalization effects. , 1994, Physical review. B, Condensed matter.

[21]  T. Brandes,et al.  Preservation of positivity by dynamical coarse graining , 2008, 0804.2374.

[22]  T. Elsaesser,et al.  FEMTOSECOND INFRARED SPECTROSCOPY OF SEMICONDUCTORS AND SEMICONDUCTOR NANOSTRUCTURES , 1999 .

[23]  Paul Harrison,et al.  THE NATURE OF THE ELECTRON DISTRIBUTION FUNCTIONS IN QUANTUM CASCADE LASERS , 1999 .

[24]  Stephan W Koch,et al.  REVIEW ARTICLE: Transient and steady-state optical nonlinearities in semiconductors , 1988 .

[25]  Andreas Wacker,et al.  Coherence and Spatial Resolution of Transport in Quantum Cascade Lasers , 2007, 0706.4202.

[26]  Mark Lee,et al.  Searching for a Solid-State Terahertz Technology , 2007, Science.

[27]  R C Iotti,et al.  Nature of charge transport in quantum-cascade lasers. , 2001, Physical review letters.

[28]  Stephan W Koch,et al.  Quantum theory of the optical and electronic properties of semiconductors, fifth edition , 2009 .

[29]  Fausto Rossi,et al.  Theory of ultrafast phenomena in photoexcited semiconductors , 2002 .

[30]  Andreas Knorr,et al.  Theory of the ultrafast nonlinear response of terahertz quantum cascade laser structures , 2006 .

[31]  A. Wacker,et al.  Self-consistent theory of the gain linewidth for quantum-cascade lasers , 2004 .

[32]  Paul Harrison,et al.  Density matrix theory of transport and gain in quantum cascade lasers in a magnetic field , 2007, cond-mat/0702508.

[33]  Paul Harrison,et al.  Self-consistent scattering theory of transport and output characteristics of quantum cascade lasers , 2002 .

[34]  Fausto Rossi,et al.  Carrier thermalization versus phonon-assisted relaxation in quantum-cascade lasers: A Monte Carlo approach , 2001 .

[35]  Qing Hu,et al.  Analysis of transport properties of tetrahertz quantum cascade lasers , 2003 .

[36]  A. Knorr,et al.  Ultrafast electron-phonon interaction of intersubband transitions : Quantum kinetics from adiabatic following to Rabi-oscillations , 2005 .

[37]  Lindberg,et al.  Ultrafast adiabatic following in semiconductors. , 1990, Physical review letters.

[38]  Dan Botez,et al.  X-valley leakage in GaAs-based midinfrared quantum cascade lasers: A Monte Carlo study , 2007 .

[39]  Thomas Elsaesser,et al.  Ultrafast phase-resolved pump-probe measurements on a quantum cascade laser , 2008 .

[40]  P. Y. Yu,et al.  Fundamentals of Semiconductors , 1995 .

[41]  Role of elastic scattering mechanisms in GaInAs∕AlInAs quantum cascade lasers , 2006 .

[42]  A. Knorr,et al.  A Bloch equation approach to intensity dependent optical spectra of light harvesting complex II , 2008, Photosynthesis Research.

[43]  J. Fricke,et al.  Transport equations including many-particle correlations for an arbitrary quantum system. General formalism , 1996, cond-mat/9610128.

[44]  O. Bonno,et al.  Modeling of electron–electron scattering in Monte Carlo simulation of quantum cascade lasers , 2005 .

[45]  M. Woerner,et al.  Quantum mechanical wavepacket transport in quantum cascade laser structures , 2006 .

[46]  J. Eberly,et al.  Optical resonance and two-level atoms , 1975 .

[47]  T. Elsaesser,et al.  Optical dephasing of coherent intersubband transitions in a quasi-two-dimensional electron gas , 2004 .

[48]  Marcella Giovannini,et al.  Femtosecond dynamics of resonant tunneling and superlattice relaxation in quantum cascade lasers , 2008 .

[49]  W. Chow,et al.  Nonequilibrium many-body theory of intersubband lasers , 2006, IEEE Journal of Quantum Electronics.

[50]  Robert S. Whitney,et al.  Staying positive: going beyond Lindblad with perturbative master equations , 2007, 0711.0074.

[51]  Thomas Elsaesser,et al.  Nonlinear response of radiatively coupled intersubband transitions of quasi-two-dimensional electrons , 2005 .

[52]  S. Hughes.  Breakdown of the area theorem: carrier-wave Rabi flopping of femtosecond optical pulses , 1998 .

[53]  Gaetano Scamarcio,et al.  Comparative analysis of resonant phonon THz quantum cascade lasers , 2007, 0911.0854.