Fast terahertz imaging using a quantum cascade amplifier
Applied Physics Letters
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Ren, Y., Wallis, R., Jessop, D., Degl'Innocenti, R., Klimont, A., Beere, H., & Ritchie, D. (2015). Fast terahertz imaging using a quantum cascade amplifier. Applied Physics Letters https://doi.org/10.1063/1.4926602
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.
This work was supported by the Engineering and Physical Sciences Research Council.
Engineering and Physical Sciences Research Council (EP/J017671/1)
External DOI: https://doi.org/10.1063/1.4926602
This record's URL: https://www.repository.cam.ac.uk/handle/1810/248872
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Licence URL: http://creativecommons.org/licenses/by-nc/2.0/uk/