High-temperature operation of broadband bidirectional terahertz quantum-cascade lasers

Journal Article · Mon Sep 12 00:00:00 EDT 2016 · Scientific Reports

DOI:https://doi.org/10.1038/srep32978· OSTI ID:1338389

Khanal, Sudeep ^[1]; Gao, Liang ^[1]; Zhao, Le ^[1]; Reno, John L. ^[2]; Kumar, Sushil ^[1]

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1. Lehigh Univ., Bethlehem, PA (United States). Dept. of Electrical and Computer Engineering
2. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Center for Integrated Nanotechnolgies

Terahertz quantum cascade lasers (QCLs) with a broadband gain medium could play an important role for sensing and spectroscopy since then distributed-feedback schemes could be utilized to produce laser arrays on a single semiconductor chip with wide spectral coverage. QCLs can be designed to emit at two different frequencies when biased with opposing electrical polarities. Here, we develop terahertz QCLs with bidirectional operation to achieve broadband lasing from the same semiconductor chip. A three-well design scheme with shallow-well GaAs/Al_0.10Ga_0.90As superlattices is developed to achieve high-temperature operation for bidirectional QCLs. It is shown that shallow-well heterostructures lead to optimal quantum-transport in the superlattice for bidirectional operation compared to the prevalent GaAs/Al_0.15Ga_0.85As material system. Furthermore, broadband lasing in the frequency range of 3.1–3.7 THz is demonstrated for one QCL design, which achieves maximum operating temperatures of 147 K and 128 K respectively in opposing polarities. Dual-color lasing with large frequency separation is demonstrated for a second QCL, that emits at ~3.7 THz and operates up to 121 K in one polarity, and at ~2.7 THz up to 105 K in the opposing polarity. Finally, these are the highest operating temperatures achieved for broadband terahertz QCLs at the respective emission frequencies, and could lead to commercial development of broadband terahertz laser arrays.

• Research Organization: Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: AC04-94AL85000
• OSTI ID: 1338389
• Report Number(s): SAND2016-12563J; 649877
• Journal Information: Scientific Reports, Vol. 6; ISSN 2045-2322
• Publisher: Nature Publishing Group
• Country of Publication: United States
• Language: English

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