Garrasi, K, Mezzapesa, FP, Salemi, L et al. (7 more authors) (2019) High Dynamic Range, Heterogeneous, Terahertz Quantum Cascade Lasers Featuring Thermally Tunable Frequency Comb Operation over a Broad Current Range. ACS Photonics, 6 (1). pp. 73-78. ISSN 2330-4022
Abstract
We report on the engineering of broadband quantum cascade lasers (QCLs) emitting at Terahertz (THz) frequencies, which exploit a heterogeneous active region scheme and have a current density dynamic range (Jdr) of 3.2, significantly larger than the state-of-the-art, over a 1.3 THz bandwidth. We demonstrate that the devised broadband lasers operate as THz optical frequency comb synthesizers, in continuous-wave, with a maximum optical output power of 4 mW (0.73 mW in the comb regime). Measurement of the intermode beatnote map reveals a clear dispersion-compensated frequency comb regime extending over a continuous 106 mA current range (current density dynamic range of 1.24), significantly broader than the state-of-the-art at similar geometries, with a corresponding emission bandwidth of ≈1.05 THz and a stable and narrow (4.15 kHz) beatnote detected with a signal-to-noise ratio of 34 dB. Analysis of the electrical and thermal beatnote tuning reveals a current-tuning coefficient ranging between 5 and 2.1 MHz/mA and a temperature-tuning coefficient of −4 MHz/K. The ability to tune the THz QCL combs over their full operating dynamic range, by temperature and current, paves the way for their use as a powerful spectroscopy tool that can provide broad frequency coverage combined with high precision spectral accuracy.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | (c) 2018, American Chemical Society. This is an author produced version of a paper published in ACS Photonics. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | broadband lasers; frequency combs; infrared photonics; quantum cascade laser; quantum optics; terahertz |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Electronic & Electrical Engineering (Leeds) > Pollard Institute (Leeds) The University of Leeds > Faculty of Medicine and Health (Leeds) > School of Medicine (Leeds) > Leeds Institute of Cardiovascular and Metabolic Medicine (LICAMM) > Specialist Science Education Dept (Leeds) |
Funding Information: | Funder Grant number EU - European Union GA 665158 EPSRC EP/P021859/1 Royal Society IEC\NSFC\170384 |
Depositing User: | Symplectic Publications |
Date Deposited: | 25 Jan 2019 14:46 |
Last Modified: | 31 Dec 2019 01:39 |
Status: | Published |
Publisher: | American Chemical Society |
Identification Number: | 10.1021/acsphotonics.8b01483 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:141359 |