Ren, Yuan and Wallis, Robert and Jessop, David Stephen and Degl'Innocenti, Riccardo and Klimont, Adam and Beere, Harvey E. and Ritchie, David A. (2015) Fast terahertz imaging using a quantum cascade amplifier. Applied Physics Letters, 107 (1). ISSN 0003-6951
Full text not available from this repository.Abstract
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 20000 points per second.