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Demonstration of air-guided quantum cascade lasers without top claddings

Moreau, V. and Bahriz, M. and Colombelli, R. and Perahia, R. and Painter, O. and Wilson, L. R. and Krysa, A. B. (2007) Demonstration of air-guided quantum cascade lasers without top claddings. Optics Express, 15 (22). pp. 14861-14869. ISSN 1094-4087.

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We report on quantum cascade lasers employing waveguides based on a predominant air confinement mechanism in which the active region is located immediately at the device top surface. The lasers employ ridge-waveguide resonators with narrow lateral electrical contacts only, with a large, central top region not covered by metallization layers. Devices based on this principle have been reported in the past; however, they employed a thick, doped top-cladding layer in order to allow for uniform current injection. We find that the in-plane conductivity of the active region - when the material used is of high quality - provides adequate electrical injection. As a consequence, the devices demonstrated in this work are thinner, and most importantly they can simultaneously support air-guided and surface-plasmon waveguide modes. When the lateral contacts are narrow, the optical mode is mostly located below the air-semiconductor interface. The mode is predominantly air-guided and it leaks from the top surface into the surrounding environment, suggesting that these lasers could be employed for surface-sensing applications. These laser modes are found to operate up to room temperature under pulsed injection, with an emission spectrum centered around λ ≃ 7:66 μm.

Item Type:Article
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Painter, O.0000-0002-1581-9209
Additional Information:© 2007 Optical Society of America. Received 10 July 2007; revised 21 August 2007; accepted 21 August 2007; published 26 October 2007. We thank C. Faugeras for help with the far-field measurements; F. Julien, C. Sirtori, O. Demichel for useful discussions, and J. Palomo for technical help. This work was conducted as part of a EURYI scheme award ( The Caltech portion of this work was supported by the DARPA Center for Optofluidics ( This work is supported by the UK Engineering and Physical Sciences Research Council (EPSRC) and by the Royal Society. The device fabrication has been performed at the nano-center “Centrale Technologique Minerve” at the Institut d’Electronique Fondamentale.
Funding AgencyGrant Number
Defense Advanced Research Projects Agency (DARPA)UNSPECIFIED
Engineering and Physical Sciences Research Council (EPSRC)UNSPECIFIED
Subject Keywords:semiconductor lasers; laser resonators, infrared lasers
Issue or Number:22
Record Number:CaltechAUTHORS:MORoe07
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Official Citation:V. Moreau, M. Bahriz, R. Colombelli, R. Perahia, O. Painter, L. R. Wilson, and A. B. Krysa, "Demonstration of air-guided quantum cascade lasers without top claddings," Opt. Express 15, 14861-14869 (2007)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:9440
Deposited By: Archive Administrator
Deposited On:02 Jan 2008
Last Modified:03 Oct 2019 00:00

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