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Florian Blanchet

Photonique Josephson: Microwave generation & amplification in the quantum regime

Published on 17 December 2018
Thesis presented December 17, 2018

Abstract:
The recent field of Josephson photonics is about the interplay between circuit quantum electrodynamic and dynamical Coulomb blockade. It explains and studies the ability of a Cooper pair to inelasticity tunnel through a DC-biased Josephson junction by dissipating the Cooper pair energy in the electromagnetic environment of the junction in the form of photons.
This thesis focuses on two aspects of the Josephson photonics:
• Control over the statistics of the emitted photons with focus on Generation of non-classical photons;
• Stimulated emission of photons leading to Amplification with added noise at the quantum limit.These devices are powered with a simple DC voltage used to biased the Josephson junction. Such devices can be a new solution in a frequencies range where only few simple alternative solutions are now available.
We have studied our devices with two theories, P-theory and input output theory, to derive working characteristics of our devices: Photon rate, gain, noise, bandwidth, compression point. The measured samples are made of niobium nitride and the electromagnetic environment of the junction is engineered to fulfil our needs. The possibility to select the photonic processes at will by engineering the electromagnetic environment permits to imagine further devices: other types of sources, wideband amplifiers, photon detectors.

Keywords:
Superconductor, Circuit, Photonique

On-line thesis.