Fast terahertz imaging using a quantum cascade amplifier

Journal Article · Mon Jul 06 00:00:00 EDT 2015 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4926602· OSTI ID:22483139

Ren, Yuan; Wallis, Robert; Jessop, David Stephen; Degl'Innocenti, Riccardo; Klimont, Adam; Beere, Harvey E.; Ritchie, David A. ^[1]

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1. Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom)

A terahertz (THz) imaging scheme based on the effect of self-mixing in a 2.9 THz quantum cascade (QC) amplifier has been demonstrated. By coupling an antireflective-coated silicon lens to the facet of a QC laser, with no external optical feedback, the laser mirror losses are enhanced to fully suppress lasing action, creating a THz QC amplifier. The addition of reflection from an external target to the amplifier creates enough optical feedback to initiate lasing action and the resulting emission enhances photon-assisted transport, which in turn reduces the voltage across the device. At the peak gain point, the maximum photon density coupled back leads to a prominent self-mixing effect in the QC amplifier, leading to a high sensitivity, with a signal to noise ratio up to 55 dB, along with a fast data acquisition speed of 20 000 points per second.

• OSTI ID: 22483139
• Journal Information: Applied Physics Letters, Vol. 107, Issue 1; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AMPLIFIERS
DATA ACQUISITION
ELECTRIC POTENTIAL
EMISSION
FEEDBACK
LASER MIRRORS
LASERS
LENSES
LOSSES
PEAKS
PHOTONS
REFLECTION
SENSITIVITY
SIGNAL-TO-NOISE RATIO
SILICON