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Electrically pumped photonic-crystal terahertz lasers controlled by boundary conditions


Semiconductor lasers based on two-dimensional photonic crystals1,2 generally rely on an optically pumped central area, surrounded by un-pumped, and therefore absorbing, regions3. This ideal configuration is lost when photonic-crystal lasers are electrically pumped, which is practically more attractive as an external laser source is not required. In this case, in order to avoid lateral spreading of the electrical current, the device active area must be physically defined by appropriate semiconductor processing. This creates an abrupt change in the complex dielectric constant at the device boundaries, especially in the case of lasers operating in the far-infrared, where the large emission wavelengths impose device thicknesses of several micrometres. Here we show that such abrupt boundary conditions can dramatically influence the operation of electrically pumped photonic-crystal lasers. By demonstrating a general technique to implement reflecting or absorbing boundaries, we produce evidence that whispering-gallery-like modes or true photonic-crystal states can be alternatively excited. We illustrate the power of this technique by fabricating photonic-crystal terahertz (THz) semiconductor lasers, where the photonic crystal is implemented via the sole patterning of the device top metallization. Single-mode laser action is obtained in the 2.55–2.88 THz range, and the emission far field exhibits a small angular divergence, thus providing a solution for the quasi-total lack of directionality typical of THz semiconductor lasers based on metal–metal waveguides4.

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Figure 1: Device details and design.
Figure 2: Light–current–voltage characteristics and laser thresholds.
Figure 3: Spectral characterizations.
Figure 4: Far-field characterizations.


  1. Yablonovitch, E. Inhibited spontaneous emission in solid-state physics and electronics. Phys. Rev. Lett. 58, 2059–2062 (1987)

    Article  ADS  CAS  Google Scholar 

  2. Sajeev, J. Strong localization of photons in certain disordered dielectric superlattices. Phys. Rev. Lett. 58, 2486–2489 (1987)

    Article  Google Scholar 

  3. Letartre, X., Monat, C., Seassal, C. & Viktorovitch, P. Analytical modeling and an experimental investigation of two-dimensional photonic crystal microlasers: Defect state (microcavity) versus band-edge state (distributed feedback) structures. J. Opt. Soc. Am. B 22, 2581–2595 (2005)

    Article  ADS  CAS  Google Scholar 

  4. Adam, A. J. L. et al. Beam pattern of terahertz quantum cascade lasers with subwavelength cavity dimensions. Appl. Phys. Lett. 88, 151105 (2006)

    Article  ADS  Google Scholar 

  5. Sakai, K. Terahertz Optoelectronics (Topics in Applied Physics, Vol. 97, Springer, 2005)

    Book  Google Scholar 

  6. Mittleman, D. Sensing with Terahertz Radiation (Springer Series in Optical Sciences, Vol. 85, Springer, 2004)

    Google Scholar 

  7. Kohler, R. et al. Terahertz semiconductor-heterostructure laser. Nature 417, 156–159 (2002)

    Article  ADS  Google Scholar 

  8. Williams, B. S. Terahertz quantum-cascade lasers. Nature Photon. 1, 517–525 (2007)

    Article  ADS  CAS  Google Scholar 

  9. Sirtori, C. et al. Long-wavelength (λ = 8–11.5 µm) semiconductor lasers with waveguides based on surface plasmons. Opt. Lett. 23, 1366–1368 (1998)

    Article  ADS  CAS  Google Scholar 

  10. Unterrainer, K. et al. Quantum cascade lasers with double metal-semiconductor waveguide resonators. Appl. Phys. Lett. 80, 3060–3062 (2002)

    Article  ADS  CAS  Google Scholar 

  11. Colombelli, R. et al. Quantum cascade surface-emitting photonic crystal laser. Science 302, 1374–1377 (2003)

    Article  ADS  CAS  Google Scholar 

  12. Schartner, S. et al. Band structure mapping of photonic crystal intersubband detectors. Appl. Phys. Lett. 89, 151107 (2006)

    Article  ADS  Google Scholar 

  13. Dunbar, L. A. et al. Design, fabrication and optical characterization of quantum cascade lasers at terahertz frequencies using photonic crystal reflectors. Opt. Express 13, 8960–8968 (2005)

    Article  ADS  Google Scholar 

  14. Zhang, H., Dunbar, A., Scalari, G., Houdré, R. & Faist, J. Terahertz photonic crystal quantum cascade lasers. Opt. Express 15, 16818–16827 (2007)

    Article  ADS  Google Scholar 

  15. Mahler, L. et al. High-performance operation of single-mode terahertz quantum cascade lasers with metallic gratings. Appl. Phys. Lett. 87, 181101 (2005)

    Article  ADS  Google Scholar 

  16. Kumar, S., Williams, B. S., Qin, Q., Lee, A. W. M. & Hu, Q. Surface-emitting distributed feedback terahertz quantum-cascade lasers in metal-metal waveguides. Opt. Express 15, 113–128 (2007)

    Article  ADS  CAS  Google Scholar 

  17. Yu, N. et al. Small-divergence semiconductor lasers by plasmonic collimation. Nature Photon. 2, 564–570 (2008)

    Article  CAS  Google Scholar 

  18. Bahriz, M., Moreau, V., Colombelli, R., Crisafulli, O. & Painter, O. Design of mid-IR and THz quantum cascade laser cavities with complete TM photonic bandgap. Opt. Express 15, 5948–5965 (2007)

    Article  ADS  Google Scholar 

  19. Sirigu, L. et al. Terahertz quantum cascade lasers based on two-dimensional photonic crystal resonators. Opt. Express 16, 5206–5217 (2008)

    Article  ADS  Google Scholar 

  20. Barbieri, S. et al. 2.9 THz quantum cascade lasers operating up to 70 K in continuous wave. Appl. Phys. Lett. 85, 1674–1676 (2004)

    Article  ADS  CAS  Google Scholar 

  21. Painter, O. et al. Two-dimensional photonic band-gap defect mode laser. Science 284, 1819–1821 (1999)

    Article  CAS  Google Scholar 

  22. Sakai, K., Miyai, E. & Noda, S. Two dimensional coupled wave theory for square-lattice photonic-crystal lasers with TM-polarization. Opt. Express 15, 3981–3990 (2007)

    Article  ADS  Google Scholar 

  23. Kohen, S., Williams, B. S. & Hu, Q. Electromagnetic modeling of terahertz quantum cascade laser waveguides and resonators. J. Appl. Phys. 97, 053106 (2005)

    Article  ADS  Google Scholar 

  24. Chassagneux, Y. et al. Terahertz microcavity lasers with subwavelength mode volumes and thresholds in the milliampere range. Appl. Phys. Lett. 90, 091113 (2007)

    Article  ADS  Google Scholar 

  25. Wiersig, J. Hexagonal dielectric resonators and microcrystal lasers. Phys. Rev. A 67, 023807 (2003)

    Article  ADS  Google Scholar 

  26. Kim, S.-H., Kim, S.-K. & Lee, Y.-H. Vertical beaming of wavelength-scale photonic crystal resonators. Phys. Rev. B 73, 235117 (2006)

    Article  ADS  Google Scholar 

  27. Vuckovic, J., Loncar, M. & Scherer, A. Surface plasmon enhanced light-emitting diode. IEEE J. Quant. Electron. 36, 1131–1144 (2000)

    Article  ADS  CAS  Google Scholar 

  28. Srinivasan, K. & Painter, O. Momentum space design of high-Q photonic crystal optical cavities. Opt. Express 10, 670–684 (2002)

    Article  ADS  Google Scholar 

  29. Colombelli, R., Ciuti, C., Chassagneux, Y. & Sirtori, C. Quantum cascade intersubband polariton light emitters. Semicond. Sci. Technol. 20, 985–990 (2005)

    Article  ADS  CAS  Google Scholar 

  30. Ciuti, C. & Carusotto, I. On the ultrastrong vacuum Rabi coupling of an intersubband transition in a semiconductor microcavity. J. Appl. Phys. 101, 081709 (2007)

    Article  ADS  Google Scholar 

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We thank J.-M. Lourtioz, F. Julien, C. Sirtori, L. Sirigu, G. Scalari and V. Moreau for discussions, P. Gellie for technical help, and J. Alton for the Golay cell. Device fabrication was performed at the CTU-IEF-Minerve, which was partially funded by the Conseil Général de l'Essonne. This work was conducted as part of a EURYI scheme award (

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Correspondence to R. Colombelli.

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This file contains Supplementary Methods, Supplementary Data , Supplementary Figures S1-S2 with Legends and Supplementary References (PDF 319 kb)

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Chassagneux, Y., Colombelli, R., Maineult, W. et al. Electrically pumped photonic-crystal terahertz lasers controlled by boundary conditions. Nature 457, 174–178 (2009).

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