[1] FAIST J,CAPASSO F,SIVCO D L,et al.. Quantum cascade laser[J]. Science,1994,264:553. [2] GMACHL C,CAPASSO F,SIVCO D L,et al.. Recent progress in quantum cascade lasers and applications[J]. Rep. Prog. Phys.,2001,64:1553-1601. [3] MASSELINK W T,SEMTSIV M P. Quantum-cascade lasers with emission wavelength 3~5 μm[J]. SPIE,2010,7836:78360U. [4] LYAKH A,PFLVGL C,DIEHL L,et al.. 1.6 W high wall plug efficiency, continuous-wave room temperature quantum cascade laser emitting at 4.6 μm[J]. Appl. Phys. Lett.,2008,92:111110. [5] LYAKH A,MAULINI R,PFL G L C,et al.. 3 W continuous-wave room temperature single-facet emission from quantum cascade lasers based on nonresonant extraction design approach[J]. Appl. Phys. Lett.,2009,95:141113. [6] SLIVKEN S,BAI Y,GOKDEN B,et al.. Current status and potential of high power mid-infrared intersubband lasers[J]. SPIE,2010,7608:76080B. [7] EVANS A,DARVISH S R,SLIVKEN S,et al.. Buried heterostructure quantum cascade lasers with high continuous-wave wall plug efficiency[J]. Appl. Phys. Lett.,2007,91:071101. [9] LYAKH A,MAULINI R,TSEKOUN A,et al.. High-performance continuous-wave room temperature 4.0 μm quantum cascade lasers with single-facet optical emission exceeding 2 W[J]. Proc. of the National Academy of Sciences,USA,2010,107(44):18799-18802. [10] CAPASSO F. High-performance midinfrared quantum cascade Lasers[J]. Opt. Eng.,2010,49(11):111102. [11] TSEKOUN A,GO R,PUSHKARSKY M,et al.. Improved performance of quantum cascade lasers via manufacturable quality epitaxial side down mounting process utilizing aluminum nitride heat sinks[J]. SPIE,2006,6127:612702. [12] LIU P Q,HOFFMAN A J,ESCARRA M D,et al.. Highly power-efficient quantum cascade lasers[J]. Nature Photonics,2009,10.1038:95-98. [13] HURGIN K,et al.. Role of interface roughness in the transport and lasing characteristics of quantum-cascade lasers[J]. Appl. Phys. Lett.,2009,94:091101. [14] SHIN J C,SOUZA M D,LIU Z,et al.. Highly temperature insensitive, deep-well 4.8 μm emitting quantum cascade semiconductor lasers[J]. Appl. Phys. Lett.,2009,94:201103. [15] BAI Y,TSAO N S,SELCUK E,et al.. Highly temperature insensitive quantum cascade lasers[J]. Appl. Phys. Lett.,2010,97:251104. [16] BOTEZ D,SHIN J C,KUMAR S,et al.. Electron leakage and its suppression via deep-well structures in 4.5 to 5.0 μm emitting quantum cascade lasers[J]. Opt. Eng.,2010,49(11):111108. [17] BAI Y B,SLIVKEN S,KUBOYA S,et al.. Quantum cascade lasers that emit more light than heat[J]. Nature Photonics,2010,4:99-102. [18] FRANZ K J,LIU P Q,RAFTERY J J J,et al.. Short injector quantum cascade lasers[J]. IEEE, J. Quantum. Elect..,2010,46(5):591-600. [19] WANKE M C,CAPASSO F,GMACHL C,et al.. Injectorless quantum cascade lasers[J]. Appl. Phys. Lett.,2001,78:3950-3952. [20] KATZ S,FRIEDRICH A,BOEHM G,et al.. Continuous wave operation of injectorless quantum cascade lasers at low temperatures[J]. Appl. Phys. Lett.,2008,92:181103. [21] SIRTORI C,CAPASSO F,FAIST J,et al.. Nonparabolicity and a sum rule associated with bound-to-bound and bound-to-continuum intersubband transitions in quantum wells[J]. Phys. Rev. B.,1994,50:8663-8674. [22] NELSON D F,MILLER R C,KLEINMANN D A. Band nonparabolicity effects in semiconductor quantum wells[J]. Phys. Rev. B.,1987,35:7770-7773. [23] VAN D E WALLE C G. Band lineups and deformation potentials in themodel-solid theory[J]. Phys. Rev. B.,1989,39:1871-1883. [24] ALARELLI M. Heterojunctions and Semiconductor Heterostucture[M]. Berlin:Springer-Verlag,1986. [25] FERREIRA R,BASTARD G. Evaluation of some scattering times for electrons in unbiased and biased single- and multiple-quantum-well structures[J]. Phys. Rev. B.,1989,40:1074-1086. [26] LIU H C,CAPASSO F. Intersubband Transitions in Quantum Wells:Physics and Device Applications II[M]. San Diego:Academic Press,2000. [27] BECK M,HOFSTETTER D,AELLEN T,et al.. Room temperature quantum cascade laser[J]. Science,2002,295:301-305. [28] RAZEGHI M. High performance InP based mid-IR quantum cascade lasers[J]. IEEE J. Sel. Top. Quantum Elect.,2009,15:941-951. [29] FAIST J. Wallplug efficiency of quantum cascade lasers:critical parameters and fundamental limits[J]. Appl. Phys. Lett.,2007,90:253512.