SMART-QDEV · Strong light-matter coupled ultra-fast and non-linear quantum semiconductor devices

This project will combine for the first time strong light-matter coupling in quantum-confined electronic systems with the optical and electronic non-linearities of semiconductor heterostructures: we will develop device concepts with unique ultra-fast, non-linear and quantum functionalities. The key ingredient is an unconventional use of the strong light-matter coupling regime (SCR), a fascinating concept that is recently transitioning from basic physics to quantum devices.We will first address fundamental physics problems, then well turn to device applications. A key conceptual building block is that the nature of optical non-linearities is radically modified when operating in the SCR. This has profound consequences. We will study few-photon non-linearities, in particular the ultimate case of devices that can sense virtual photons. This will lead us to device concepts whose behavior is enabled by vacuum-field photons, bringing us radically beyond the state of art. We will then move to the case of many photons. We will focus on absorption saturation, that explored only in the weak coupling regime, where it is difficult to engineer. We have discovered that in the SCR instead it becomes tailorable and previously unavailable functionalities can be envisioned. This has profound consequences: we will demonstrate semiconductor saturable absorber mirrors (SESAM) for the mid-IR spectral range, a technology that revolutionized ultra-fast lasers in the near-IR, but is missing at longer wavelengths. We will apply them to fiber and interband cascade lasers, radically advancing the potential of those sources. These are ground-breaking demonstrations for mid-IR science and technology. SMART-QDEV is a project rooted in fundamental physics research, able to open up new horizons and research opportunities on longer-term and visionary topics. At the same time, SMART-QDEV has a clear vision for applications.