Description du sujet de thèse

An electro-optic modulator is a device allowing the modulation of a beam of light by means of an applied electrical signal. The modulation can be imprinted on different properties of the light beam: amplitude, phase, frequency or polarization of the beam. They are essential in several applications like telecommunications, image projections, displays. Phase modulators are extremely important in quantum technologies: they are used to produce entangled light states in photonic platforms, or to optically address and/or prepare quantum bits.
While they are commercially available in the visible and near-infrared range, electro-optic modulators are at their infancy as far as mid-infrared wavelengths are concerned. Recently, our group has developed an amplitude modulator based on the Stark effect in a system of tunnel coupled quantum wells. This device allowed us to realize a data transmission experiment in the free-space, with record bitrate.

The aim of this project is the realization of phase modulators in the mid-infrared. Such devices will be implemented in a waveguide geometry, and they will be exploited to realize a Mach-Zehnder interferometer. Combined with a sensitive mid-infrared detector, such interferometer would be the first building block for a fully integrated heterodyne detection5 platform, opening the path towards extending the realm of quantum optics towards the mid-infrared domain.

Contexte de travail

The PhD work will be realised within the QUAD group at LPENS, in relation with the ANR project ImPALA, lead by Baptiste Chomet.

Contraintes et risques

The devices will be fabricated in the clean room of the Paris Center network. The PhD student will be trained to micro and nanofabrication techniques.