Continuous wave operation of a superlattice quantum cascade laser emitting at 2 THz

Optics Express

Volumn 14, Issue 1, 2006, Pages 171-181

  Worral, Chris ^a   Alton, Jesse ^d   Houghton, Mark ^d   Barbieri, Stefano ^d   Beere, Harvey E ^a   Ritchie, David ^a   Sirtori, Carlo ^b,c  

^a UNIVERSITY OF CAMBRIDGE   (United Kingdom)

^b UNIVERSITÉ PARIS DIDEROT   (France)

^c THALES RESEARCH AND TECHNOLOGY   (France)

^d NONE

Author keywords

[No Author keywords available]

Indexed keywords

BAND STRUCTURE; CURRENT DENSITY; HETEROJUNCTIONS; OPTICAL WAVEGUIDES; QUANTUM OPTICS; SUPERLATTICES;

LASING; METALLIC WAVEGUIDES; PEAK POWER; QUANTUM CASCADE LASERS;

LASER OPTICS;

EID: 30344464077     PISSN: 10944087     EISSN: 10944087     Source Type: Journal    
DOI: 10.1364/OPEX.14.000171     Document Type: Article

References (22)

1. R. Köhler, A. Tredicucci, F. Beltram, H. E. Beere, E. H. Linfield, A. G. Davies, D. A. Ritchie, R. C. Iotti, and F. Rossi, "Terahertz semiconductor-heterostructure laser," Nature 417, 156 (2002)
2. B. S. Williams, S. Kumar, and Q. Hu, "Operation of THz Quantum cascade lasers at 164K in pulsed mode and at 117K in continuous-wave mode," Opt. Express 13, 3331 (2005)
3. B. S. Williams, S. Kumar, Q. Hu, and J.L. Reno "Resonant-phonon terahertz quantum cascade laser operating at 2.1 THz (X = 141 μm)," Electron. Lett. 40, 431 (2004)
4. G. Scalari, S. Blaser, J. Faist, H. Beere, E. Linfield, D. Ritchie, and G. Davies, "Terahertz emission from quantum cascade lasers in the quantum Hall regime: evidence for many-body resonances and localization effects," Phys. Rev. Lett. 93, 237403-1 (2004)
5. th International Conference on Intersubband transitions in Quantum Wells, ITQW 2005, Cape Cod, MA, Abstract book (2005).
6. H. Willenberg, G. H. Döhler, and J. Faist, "Intersubband gain in a Bloch oscillator and quantum cascade laser," Phys. Rev. B 67, 085315 (2003).
7. R. Ferreira, and G. Bastard, "Evaluation of some scattering times for electrons in unbiased and biased single- and multiple-quantum-well structures," Phys. Rev. B 40, 1076 (1989).
8. Y. C. Shen, T. Lo, P. F. Taday, B. E. Cole, W. R. Tribe, and M. C. Kemp, "Detection and identification of explosives using THz pulsed spectroscopic imaging," Appl. Phys. Lett. 86, 241116 (2005)
9. W. R Tribe, D. A. Newnham, P. F. Taday, and M. C. Kemp, "Hidden object detection: security applications of THz technology," Proc. SPIE Int. Soc. Opt. Eng. 5434, 168 (2004)
10. J. R. Gao, J. N. Hovenier, Z. Q. Yang, J. J. A. Baselmans, A. Baryshev, M. Hajenius, T. M. Klapwijk, A. J. L. Adam, T. O. Klaassen, B. S. Williams, S. Kumar, Q. Hu, and J. L. Reno, "Terahertz heterodyne receiver based on a quantum cascade laser and a superconducting bolometer," Appl. Phys. Lett. 86, 244104 (2005)
11. S. Barbieri, J. Alton, H. E. Beere, J. Fowler, E. H. Linfield, and D. A. Ritchie, "2.9 THz quantum cascade laser operating up to 70K in continuous wave," Appl. Phys. Lett. 85, 1674 (2004)
12. T. Unuma, M. Yoshita, T. Noda, H. Sakaki, and H. Akiyama, "Intersubband absorption linewidth in GaAs quantum wells due to scattering by interface roughness, phonons, ally disorder, and impurities," Appl. Phys. Lett. 93, 1586 (2003).
13. J. Alton, S. Barbieri, H. E. Beere, J. Fowler, E. H. Linfield, and D. A. Ritchie, "Optimum resonant tunnelling injection and influence of doping density on the performance of bound-to-continuum THz quantum cascade lasers," Proc. SPIE Int. Soc. Opt. Eng. 5727, 65 (2005)
14. The etch-stop layer beneath the active region is not relevant for this work, and was grown in order to allow the fabrication of a double metal waveguide. See for example: S. S. Dhillon, J. Alton, S. Barbieri, C. Sirtori, A. de Rossi, M. Calligaro, H. E. Beere, and D. A. Ritchie, "Ultra-low threshold current quantum cascade lasers based on double-metal buried strip waveguides," Appl. Phys. Lett. 87, 071107 (2005)
15. The dielectric constants of the doped GaAs layers were computed on the basis of the classical Drude model of the conductivity, with a scattering time of 1 ps in the AR, and of 0.1 ps elsewhere.
16. C. Sirtori, F. Capasso, J. Faist, A. L. Hutchinson, D. L. Sivco, and A. Y. Cho, "Resonant tunnelling in quantum cascade lasers," IEEE J. Quantum Electron. 34, 1722 (1998)
17. More realistic calculations of the reflectivity are under way. See C. M. Herzinger, C. C. Lu, T. A. DeTemple, and W. C. Chew, IEEE J. Quantum Electron. 29, 2273 (1993).
18. Recently, we observed laser emission at 1.94 THz with devices processed from a nominally identical growth of the present QCL.
19. These findings were confirmed by magneto transport measurements at low biases. At constant voltage we observed periodic oscillations of the current density as a function of 1/B, where B is the intensity of a magnetic field applied parallel to the growth axis. At any voltage, and down to 0.5V, we measured a constant periodicity, from which we derived a transition energy of 8.3 meV. C. Worral et al., unpublished data. For a description of the technique see: J. Alton, S. Barbieri, J. Fowler, J. Muscat, H. E. Beere, E. H. Linfield, A. G. Davies, D. A . Ritchie, R. Khöler, and A. Tredicucci, "Magnetic-field in-plane quantization and tuning of population inversion in a THz superlattice quantum cascade laser," Phys. Rev. B 68, 081303R (2003).
20. M. F. Pereira, Jr., S. -C. Lee, and A. Wacker, "Controlling many-body effects in the midinfrared gain and terahertz absorption of quantum cascade structures," Phys. Rev. B. 69, 205310 (2004).
21. M. S. Vitiello, G. Scamarcio, V. Spagnolo, B. S. Williams, S. Kumar, Q. Hu, and J. L. Reno, "Measurement of subband electronic temperatures and population inversion in THz quantum-cascade lasers," Appl. Phys. Lett. 86, 111115 (2005).
22. th, vs T curves of Fig. 5 are representative of several devices with different cavity lengths.