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Proceedings Paper

Terahertz quantum cascade laser sources based on Čerenkov difference-frequency generation
Author(s): Karun Vijayraghavan; Augustinas Vizbaras; Robert W. Adams; Min Jang; Christian Grasse; Gerhard Boehm; Markus C. Amann; Mikhail A. Belkin
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Paper Abstract

Room-temperature terahertz (THz) quantum cascade laser (QCL) sources based on intra-cavity difference-frequency generation (DFG) with record THz conversion efficiencies is reported. THz DFG QCLs reported previously are highly inefficient since THz radiation produced more than ~100 μm away from the exit facet is fully absorbed due to high THz losses in the QCL waveguide. Our lasers use a non-collinear Čerenkov DFG scheme to extract THz radiation from the active region. Dual-color mid-infrared quantum cascade lasers with integrated giant optical nonlinearity are grown on semi-insulating (S.I.) InP substrates. A lateral current extraction scheme is used. THz radiation is emitted at an angle into the substrate with respect to the mid-infrared pumps. Since S.I. InP is virtually lossless to THz radiation, this scheme allows for efficient extraction of THz radiation along the whole waveguide length. As a result, our sources demonstrate large mid-infrared-to-THz conversion efficiency and directional THz output. Experimentally, proof-of-principle devices demonstrate a conversion efficiency up to 70 μW/W2 and provide output across a 1.2 - 4.5 THz spectral range.

Paper Details

Date Published: 15 October 2012
PDF: 7 pages
Proc. SPIE 8496, Terahertz Emitters, Receivers, and Applications III, 849608 (15 October 2012); doi: 10.1117/12.929343
Show Author Affiliations
Karun Vijayraghavan, The Univ. of Texas at Austin (United States)
Augustinas Vizbaras, Walter Schottky Institut (Germany)
Robert W. Adams, The Univ. of Texas at Austin (United States)
Min Jang, The Univ. of Texas at Austin (United States)
Christian Grasse, Walter Schottky Institut (Germany)
Gerhard Boehm, Walter Schottky Institut (Germany)
Markus C. Amann, Walter Schottky Institut (Germany)
Mikhail A. Belkin, The Univ. of Texas at Austin (United States)

Published in SPIE Proceedings Vol. 8496:
Terahertz Emitters, Receivers, and Applications III
Manijeh Razeghi; Alexei N. Baranov; Henry O. Everitt; John M. Zavada; Tariq Manzur, Editor(s)

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