Quantum correlAtions in TerAhertz qcl COMBs

Quantum technology (QT) migration to the terahertz (THz) frequency range is technologically challenging, although of huge technological potential. In fact, continuous-variable entangled THz states preparation can become the founding blocks for future implementation of quantum computation protocols, quantum teleportation or to increase capacity, robustness and security of selected free-space quantum communication channels. For example, the peculiar features of THz radiation, transmissivity through otherwise opaque materials, or robustness with respect to Rayleigh scattering, can potentially allow a plethora
of frontier applications, such as quantum-secured fast digital data transfer in opaque or harsh environments (dust, smog, particulate) or quantum-enhanced sensitivity in spectroscopic and metrological THz setups. The goal of QATACOMB is to develop a miniaturized solid-state platform for generation, detection and complete characterization of non-classical squeezed states of THz frequency light. This will exploit THz quantum cascade laser (QCL) frequency combs (FCs) as nonlinear sources, coupled with graphene nanoscale quantum sensors and cavity-coupled ultrafast coherent detectors. QCLs are, to date,
the most efficient miniaturized lasers at THz frequencies. Their broad gain and controlled group velocity dispersion has recently enabled compact FC generation, based on four-wave mixing (FWM) processes that take place within the gain medium. As a consequence, QCLs are ideal candidates for the generation of multi-mode squeezed states of light, due to the presence of quantum-correlated side-band modes.

CONSORTIUM

• Coordinator: Luigi Consolino (Consiglio Nazionale delle Ricerche, IT)
• Christian Jirauschek (Technische Universität München, DE)
• Sukhdeep Dhillon (Centre National de la Recherche Scientifique, FR)

PROJECT POSTER: QATACOMB