In microdisk lasers1,2,3 a ring resonator is formed by successive total internal reflections inside a circularly shaped waveguide. The photon lifetime of the resulting whispering gallery optical modes is limited mainly by the waveguide absorption. Light is usually coupled out by tunnelling owing to the disk curvature or through imperfections at the border, but the output power is hard to exploit in a potential application because the emission is mainly in the disk plane and isotropic. Here we realize vertically emitting whispering gallery lasers by implementing appropriate diffraction gratings along the disk circumference. We use terahertz quantum cascade structures4,5 and demonstrate a 50–fold increase in the optical power compared to devices without gratings, while at the same time engineering the lasing spectrum according to the grating rotational symmetry. This concept will allow the fabrication of compact arrays of single-mode terahertz sources with regular beam profiles and high output power.
This is a preview of subscription content, access via your institution
Subscribe to this journal
Receive 12 print issues and online access
$209.00 per year
only $17.42 per issue
Rent or buy this article
Prices vary by article type
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
McCall, S. L., Levi, A. F. J., Slusher, R. E., Pearton, S. J. & Logan, R. A. Whispering-gallery mode microdisk lasers. Appl. Phys. Lett. 60, 289–291 (1992).
Faist, J. et al. Quantum cascade disk lasers. Appl. Phys. Lett. 69, 2456–2458 (1996).
Tredicucci, A. et al. Very long wavelength (λ≈16 µm) whispering gallery mode microdisk lasers. Electron. Lett. 36, 328–330 (2000).
Köhler, R. et al. Terahertz semiconductor-heterostructure laser. Nature 417, 156–159 (2002).
Williams, B. S. Terahertz quantum-cascade lasers. Nature Photon. 1, 517–525 (2007).
Fasching, G. et al. Terahertz microcavity quantum-cascade lasers. Appl. Phys. Lett. 87, 211112 (2005).
Chassagneux, Y. et al. Terahertz microcavity lasers with subwavelength mode volumes and thresholds in the milliampere range. Appl. Phys. Lett. 90, 091113 (2007).
Dunbar, L. A. et al. Small optical volume terahertz emitting microdisk quantum cascade lasers. Appl. Phys. Lett. 90, 141114 (2007).
Amanti, M., Fischer, M., Walther, C., Scalari, G. & Faist, J. Horn antennas for terahertz quantum cascade lasers. Electron. Lett. 43, 573–574 (2007).
Lee, A. W. M. et al. High-power and high-temperature THz quantum-cascade lasers based on lens-coupled metal–metal waveguides. Opt. Lett. 32, 2840–2842 (2007).
Demichel, O. et al. Surface plasmon photonic structures in terahertz quantum cascade lasers. Opt. Express 14, 5335–5345 (2006).
Fan, J. A. et al. Surface emitting terahertz quantum cascade laser with a double-metal waveguide. Opt. Express 14, 11672–11680 (2006).
Kumar, S. et al. Surface-emitting distributed feedback terahertz quantum-cascade lasers in metal–metal waveguides. Opt. Express 15, 113–128 (2007).
Colombelli, R. et al. Quantum cascade surface-emitting photonic crystal laser. Science 302, 1374–1377 (2003).
Sirigu, L. et al. Terahertz quantum cascade lasers based on two-dimensional photonic crystal resonators. Opt. Express 16, 5206–5217 (2008).
Levi, A. F. J. et al. Directional light coupling from microdisk lasers. Appl. Phys. Lett. 62, 561–563 (1993).
Fujita, M. & Baba, T. Microgear laser. Appl. Phys. Lett. 80, 2051–2053 (2002).
Nockel, J. U., Stone, A. D., Chen, G., Grossman, H. L. & Chang, R. K. Directional emission from asymmetric resonant cavities. Opt. Lett. 21, 1609–1611 (1996).
Gmachl, C. et al. High-power directional emission from microlasers with chaotic resonators. Science 280, 1556–1564 (1998).
Srinivasan, K. et al. Optical loss and lasing characteristics of high-quality-factor AlGaAs microdisk resonators with embedded quantum dots. Appl. Phys. Lett. 86, 151106 (2005).
Schubert, M. & Rana, F. Analysis of terahertz surface emitting quantum-cascade lasers. IEEE J. Quant. Electron. 42, 257–265 (2006).
Bolivar, P. H. et al. Label-free THz sensing of genetic sequences: towards ‘THz biochips’. Philos. Trans. R. Soc. A—Math. Phys. Eng. Sci. 362, 323–333 (2004).
Kumar, S., Williams, B. S., Kohen, S. & Hu, Q. Continuous-wave operation of terahertz quantum-cascade lasers above liquid-nitrogen temperature. Appl. Phys. Lett. 84, 2494–2496 (2004).
This work was supported in part by the European Commission through the Research and Training Network ‘Physics of Intersubband Semiconductor Emitters’ and the integrated project ‘Teranova’. We also acknowledge support from the Italian Ministry of Research through the project ‘National Laboratory for Nanotechnology applied to Genomics and Post-Genomics’.
About this article
Cite this article
Mahler, L., Tredicucci, A., Beltram, F. et al. Vertically emitting microdisk lasers. Nature Photon 3, 46–49 (2009). https://doi.org/10.1038/nphoton.2008.248
This article is cited by
Scientific Reports (2022)
Light: Science & Applications (2021)
Light: Science & Applications (2017)
Nature Reviews Materials (2016)
Efficient power extraction in surface-emitting semiconductor lasers using graded photonic heterostructures
Nature Communications (2012)