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Quantum cascade lasers that emit more light than heat

Nature Photonics volume 4, pages 99102 (2010) | Download Citation


For any semiconductor lasers, the wall plug efficiency, that is, the portion of the injected electrical energy that can be converted into output optical energy, is one of the most important figures of merit. A device with a higher wall plug efficiency has a lower power demand and prolonged device lifetime due to its reduced self-heating. Since its invention, the power performance of the quantum cascade laser1 has improved tremendously2,3,4,5,6,7. However, although the internal quantum efficiency7,8 can be engineered to be greater than 80% at low temperatures, the wall plug efficiency of a quantum cascade laser has never been demonstrated above 50% at any temperature. The best wall plug efficiency reported to date is 36% at 120 K (ref. 9). Here, we overcome the limiting factors using a single-well injector design and demonstrate 53% wall plug efficiency at 40 K with an emitting wavelength of 5 µm. In other words, we demonstrate a quantum cascade laser that produces more light than heat.

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The authors would like to acknowledge the support, interest and encouragement of R. Leheny, H. Temkin and M. Rosker from the Defense Advanced Research Projects Agency, M. E. Gross from the Office of Naval Research, and experts from the Naval Research Laboratory and the Army Research Office.

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  1. Center for Quantum Devices, Department of Electrical Engineering and Computer Science, Northwestern University, Evanston, Illinois 60208, USA

    • Yanbo Bai
    • , Steven Slivken
    • , Shigeyuki Kuboya
    • , Shaban R. Darvish
    •  & Manijeh Razeghi


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Y.B. designed the laser core structure, fabricated the device, performed the testing and wrote the paper. S.S. designed the waveguide structure, grew the wafer with GS-MBE and wrote the paper. S.K. carried out buried ridge regrowth with MOCVD and S.R.D. conducted the regrowth processing. M.R. provided the idea and supervised the project.

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The authors declare no competing financial interests.

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Correspondence to Manijeh Razeghi.

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