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Reference : UMR8023-ANGVAS-004
Workplace : PARIS 05
Date of publication : Friday, June 19, 2020
Scientific Responsible name : Carlo Sirtori
Type of Contract : PhD Student contract / Thesis offer
Contract Period : 36 months
Start date of the thesis : 1 September 2020
Proportion of work : Full time
Remuneration : 2 135,00 € gross monthly
Description of the thesis topic
High performance semiconductor photodetectors are key devices for the development of quantum technologies. In the THz and mid-infrared ranges these devices are still a great challenge as the small photon energy is intimately related to a large noise that hinders their sensitivity and imposes cryogenic operation. In the wavelength band between 8 and 12 µm we have recently implemented quantum well infrared photodetectors into a metamaterial made of subwavelength metallic resonators. These devices show enhanced performances up to room temperature with relatively high sensitivities . Moreover, they are intrinsically very fast and combine high sensitivity at room temperature with a very fast frequency response, in the tens of GHz range. These properties have been exploited for implementing a heterodyne detection scheme in which the minimum detectable power is few pW. Remarkably, no physical limits prevent to further increase the system sensitivity and reach the photon counting edge.
The aim of this thesis will be to push the boundaries of the THz detection to the ultimate limit by conceiving new metamaterial detectors and improving the heterodyne setup. This will include an active frequency stabilization of the system  and a balanced detection scheme that will allow us take full benefit of the high frequency and low noise properties of heterodyne technique. Several applications as sensing, communications and few photons coherent non-destructive detection will be enabled by this technology. The work will be performed at LPENS, in the Quantum Physics and Devices group (QUAD).
 D. Palaferri et al., Room-temperature nine-µm-wavelength photodetectors and GHz-frequency heterodyne receivers, Nature 556, 85 (2018)
 B. Argence, et al., Quantum cascade laser frequency stabilization at the sub-Hz level, Nature Photonics. 9, 456 (2015).
The work will be performed at LPENS, in the Quantum Physics and Devices group (QUAD).
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