Quantum-confined electronic semiconductor systems operating in the strong light-matter coupling regime acquire radically new optical non-linear properties. SMART-QDEV will leverage this to demonstrate a new class of semiconductor devices with engineered ultra-fast non-linear functionalities.

The project, that will start in September 2024, will target the mid-infrared spectral range (3mm<l<30mm), of importance because gases exhibit characteristic spectral absorption lines. One of the core objectives is to develop compact and practical mode-locked sources and frequency combs, that are currently missing in this region of the spectrum. In particular, ultra-fast semiconductor saturable absorption mirrors (SESAM) will be demonstrated over the whole mid-infrared spectral range. SESAMs have revolutionized ultra-fast lasers in the near-infrared, but have not been available as yet at longer wavelengths. This development will then be applied to interband cascade lasers and fiber lasers, leading to radical advances for laser comb technology.

The second thrust of the project dives into fundamental physics: we will study the limit of few-photon nonlinearities, down to the ultimate case of devices that can “sense” virtual photons. The ultimate goal is to develop devices whose operation is affected by vacuum-field photons, a purely quantum electro-dynamical effect, developing a new concept of proximity sensor based on cavity electrodynamics.
The project will benefit from the rich C2N environment in terms of nano-fabrication possibilities with the Centrale de Technologie PIMENT, and in terms of internal scientific collaborations.

Figure 1 - Bottom: cavity architecture for exploiting non-linearities in the strong coupling regime: active QWs (pink) embedded in highly confining metal cavities (yellow).
Top: Tailorable saturation intensity as a function of the light-matter coupling strength, and potential devices for the different regimes.