TeraMicroCav

The goal of the project is to study the potential of optical semiconductor microcavities as THz detectors and emitters. We propose here to explore the possibility of detecting and generating THz radiation in semiconductor microcavities by using THz radiative transitions between polaritonic states. Polariton physics is now well known and especially well mastered by the three project partners (LKB, LPA, LPN). The investigated polariton states are separated in energy by typically a few meV (i.e. in the THz range). If the THz radiative transitions between the polariton branches are normally forbidden by the selection rules, different theoretical proposals open the way for engineering the band structure to allow the absorption or radiative emission of THz photons. A particularly interesting aspect of this project lies in using the peculiar properties of polaritons to avoid the low temperature constraint usually required by thermodynamics principles. The objective of the project is the realization of THz detectors operating at liquid nitrogen temperature with high detectivity in compact geometries, compatible with the development of semiconductor based devices. Conversely and in similar schemes, we will study the potential of such semiconductor microcavities for THz emission by using the bosonic stimulation regime (polariton lasing).. Different strategies proposed by the theory to allow THz radiative transitions will be implemented in the design and fabrication of a new family of semiconductor microcavities and micropillars. These structures will then be studied in the field of optics and THz using methods controlled by three partners: - LPA brings its expertise and experimental facilities in the field of THz spectroscopy, optical spectroscopy and theory - LKB brings its expertise and experimental facilities in the optical study of polaritons under "two-photon" and non-linear excitation of the polariton states - LPN provides expertise on the sample fabrication as well as its expertise on polariton lasers.