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arXiv · 1304.3207

Continuous-wave coherent imaging with terahertz quantum cascade lasers using electro-optic harmonic sampling

Marco Ravaro·Vishal Jagtap·Giorgio Santarelli·Carlo Sirtori·Lianhe Li·S. P. Khanna·Edmund H. Linfield·Stefano Barbieri
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Abstract

We demonstrate a coherent imaging system based on a terahertz (THz) frequency quantum cascade laser (QCL) phase-locked to a near-infrared fs-laser comb. The phase locking enables coherent electro-optic sampling of the continuous-wave radiation emitted by the QCL through the generation of a heterodyne beat-note signal. We use this beat-note signal to demonstrate raster scan coherent imaging using a QCL emitting at 2.5 THz. At this frequency the detection noise floor of our system is of 3 pW/Hz and the long-term phase stability is <3 degrees/h, limited by the mechanical stability of the apparatus.

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Marco Ravaro, Vishal Jagtap, Giorgio Santarelli, Carlo Sirtori, Lianhe Li, S. P. Khanna, Edmund H. Linfield, Stefano Barbieri. 2013-04-11. Continuous-wave coherent imaging with terahertz quantum cascade lasers using electro-optic harmonic sampling. https://doi.org/10.1063/1.4793424

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