PhD on the realisation of highly sensitive photodetectors for enabling quantum optics in the mid/...

The PhD work will take place in the Quantum Physics and Devices group at LPENS laboratory.

The quest for extending the realm of quantum optics into the mid/far-infrared, at wavelength ~ 10 µm, necessitates ultra-sensitive detectors and precisely controlled light emitters for the realization of photon counters and squeezed light generators, respectively. These devices will allow the investigation of fundamental phenomena and also enable progresses for several applications such as quantum communications, environmental sensing and ultra-low coherent photon detection for the discovery of exoplanets in the galaxy.
The work of this PhD thesis will consist in conceiving and realising a new generation of detectors with ultra-high sensitivity for exploring the quantum properties of optical combs generated using quantum cascade lasers. To enhance the sensitivity of these detectors, the PhD student will explore structures where the detector is integrated with other quantum devices to amplify the photocurrent signal and block the dark current, which is the major source of noise in the mid/far-infrared.
Detector integration will begin with the study of resonant metamaterials to enhance the absorption quantum efficiency, then it will focus on the optimum coupling of the photoexcited electrons into a single electron transistor and finally on the amplification of very small signal to reach sensitivity down to the single photon counters. The hybridisation of conventional semiconductors with two-dimensional materials will also be considered for these photon assisted transistor architectures.
The ultimate goal of this project will be the use of these detectors to investigate the degree of squeezing of the light emitted by a quantum cascade laser. This will be performed by an accurate system of balance detection capable to measure light coherence in both quadratures. The use of squeezed light in the mid/far infrared will enable photon detection below the shot noise, therefore with unprecedent degree of sensitivity in this wavelength range.