An indirectly pumped terahertz quantum cascade laser with low injection coupling strength operating above 150 K

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/Al0.25Ga0.75As 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 (1.3ℏω/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 e...

[1]  E. Dupont,et al.  Simplified density-matrix model applied to three-well terahertz quantum cascade lasers , 2010 .

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

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

[4]  Qi Jie Wang,et al.  Microscopic density matrix model for optical gain of terahertz quantum cascade lasers : many-body, nonparabolicity, and resonant tunneling effects , 2012 .

[5]  R. Rosenfeld.  Nature , 2009, Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery.

[6]  F. Rossi,et al.  Impact of nonequilibrium phonons on the electron dynamics in terahertz quantum cascade lasers , 2010 .

[7]  Q. Hu,et al.  Coherence of resonant-tunneling transport in terahertz quantum-cascade lasers , 2009, 0910.2959.

[8]  Q. Hu,et al.  Effects of stimulated emission on transport in terahertz quantum cascade lasers based on diagonal designs , 2012 .

[9]  Qing Hu,et al.  Operation of terahertz quantum-cascade lasers at 164 K in pulsed mode and at 117 K in continuous-wave mode. , 2005, Optics express.

[10]  Gerhard Klimeck,et al.  Design concepts of terahertz quantum cascade lasers: Proposal for terahertz laser efficiency improvements , 2010 .

[11]  Tsuneya Ando,et al.  Line Width of Inter-Subband Absorption in Inversion Layers: Scattering from Charged Ions , 1985 .

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

[13]  Hirofumi Kan,et al.  Indirect pump scheme for quantum cascade lasers: dynamics of electron-transport and very high T0-values. , 2008, Optics express.

[14]  Z. R. Wasilewski,et al.  A phonon scattering assisted injection and extraction based terahertz quantum cascade laser , 2012, 1201.4189.

[15]  Qing Hu,et al.  Ground state terahertz quantum cascade lasers , 2012 .

[16]  Paolo Lugli,et al.  Temperature performance analysis of terahertz quantum cascade lasers: Vertical versus diagonal designs , 2010, 1106.3213.

[17]  Jerome Faist,et al.  Intersubband gain in a Bloch oscillator and Quantum cascade laser , 2003 .

[18]  A. Wacker,et al.  Nonequilibrium Green’s Function Model for Simulation of Quantum Cascade Laser Devices Under Operating Conditions , 2013, IEEE Journal of Selected Topics in Quantum Electronics.

[19]  Andreas Wacker,et al.  Extraction-controlled quantum cascade lasers , 2010, 1007.5407.

[20]  P. Vogl,et al.  Nonequilibrium Green’s function calculation for four-level scheme terahertz quantum cascade lasers , 2009 .

[21]  Paul Harrison,et al.  Mechanisms of temperature performance degradation in terahertz quantum-cascade lasers , 2003 .

[22]  Mauro F. Pereira,et al.  Nonequilibrium many body theory for quantum transport in terahertz quantum cascade lasers , 2009 .

[23]  B. Williams,et al.  1.9 THz Quantum-cascade Lasers with One-well Injector , 2006 .

[24]  J. Reno,et al.  A 1.8-THz quantum cascade laser operating significantly above the temperature of ℏω/kB , 2011 .

[25]  K. M. Chung,et al.  Terahertz quantum cascade lasers operating up to ∼ 200 K with optimized oscillator strength and improved injection tunneling. , 2012, Optics express.

[26]  Norihiko Sekine,et al.  Bloch gain in quantum cascade lasers , 2007 .

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

[28]  E. Linfield,et al.  Terahertz semiconductor-heterostructure laser , 2002, Nature.

[29]  Qi Jie Wang,et al.  High-Temperature Operation of Terahertz Quantum Cascade Laser Sources , 2009, IEEE Journal of Selected Topics in Quantum Electronics.

[30]  Sushil Kumar,et al.  Operation of terahertz quantum cascade lasers above 160 K covering a frequency range of 2-4 THz , 2012, Optical Engineering + Applications.

[31]  Jérôme Faist,et al.  Semiconductor nanowires for highly sensitive, room-temperature detection of terahertz quantum cascade laser emission , 2012 .

[32]  R. Terazzi,et al.  Sequential resonant tunneling in quantum cascade lasers , 2008, 0810.0146.

[33]  Qing Hu,et al.  Effect of oscillator strength and intermediate resonance on the performance of resonant phonon-based terahertz quantum cascade lasers , 2013 .

[34]  M. Kisin,et al.  Electron–plasmon relaxation in quantum wells with inverted subband occupation , 1998 .

[35]  S. G. Razavipour,et al.  On metal contacts of terahertz quantum cascade lasers with a metal–metal waveguide , 2011 .

[36]  Sahand Hormoz,et al.  Terahertz quantum cascade lasers with copper metal-metal waveguides operating up to 178 K. , 2008, Optics express.

[37]  G. Bastard,et al.  Free-carrier absorption in quantum cascade structures , 2011, 1112.1822.

[38]  Peter Vogl,et al.  Theory of nonequilibrium quantum transport and energy dissipation in terahertz quantum cascade lasers , 2009 .

[39]  Qing Hu,et al.  186 K Operation of Terahertz Quantum-Cascade Lasers Based on a Diagonal Design , 2009 .

[40]  R. Terazzi,et al.  Population inversion by resonant tunneling in quantum wells , 2007 .

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

[42]  J. Reno,et al.  Two-well terahertz quantum-cascade laser with direct intrawell-phonon depopulation , 2009 .

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

[44]  G. Scamarcio,et al.  Electronic temperatures of terahertz quantum cascade active regions with phonon scattering assisted injection and extraction scheme. , 2013, Optics express.

[45]  Gerhard Klimeck,et al.  Indirectly pumped 3.7 THz InGaAs/InAlAs quantum-cascade lasers grown by metal-organic vapor-phase epitaxy. , 2012, Optics express.

[46]  Jérôme Faist,et al.  Quantum cascade lasers operating from 1.2to1.6THz , 2007 .

[47]  Qi Jie Wang,et al.  Design of three-well indirect pumping terahertz quantum cascade lasers for high optical gain based on nonequilibrium Green's function analysis , 2012 .

[48]  G. Bastard,et al.  Relevance of intra- and inter-subband scattering on the absorption in heterostructures , 2012, 1207.7289.

[49]  H. Sakaki.  Physical limits of heterostructure field-effect transitors and possibilities of novel quantum field-effect devices , 1986 .

[50]  G. Karunasiri,et al.  Nonequilibrium electron leakage in terahertz quantum cascade structures , 2012 .

[51]  Paolo Lugli,et al.  Improved terahertz quantum cascade laser with variable height barriers , 2012 .

[52]  C. Gmachl,et al.  Voltage Tunability of Quantum Cascade Lasers , 2009, IEEE Journal of Quantum Electronics.