Multifunctional Flat Quantum Sources

ongoing

MultiFlaQS aims to develop efficient multifunctional sources of quantum light, namely entangled photon pairs and triplets, and squeezed states, based on ‘flat’ platforms, i.e., ultrathin layers and metasurfaces. The advantages of flat quantum sources (FlaQS) include: (i) small footprint and integrability; (ii) ultrabroadband and ultrafast operation; (iii) the possibility to combine several functionalities in the same device. Unlike linear and nonlinear ‘flat’ optics, which were developing for almost two decades, FlaQS appeared only recently, and mainly included single-photon sources. A few years ago, also FlaQS of entangled photons emerged; however, their efficiency is low and the advantages of the ‘flat’ geometry are not fully used. Generation of multiphoton quantum states, such as squeezed or graph states, is still a challenge. Most importantly, multifunctional operation has not been demonstrated. MultiFlaQS will make a decisive new step in developing FlaQS, one of paramount importance for quantum photonic technology. The following objectives are set: - Efficient generation of two-photon states and squeezed states, and their use in quantum sensing; - First-time generation of three-photon states through a direct decay of one photon into three; - Implementation of multiple functionalities: generation of quantum states, their frequency conversion and quantum operations on them. To meet them, the applicant will combine her quantum optics and quantum information expertise, including pioneering steps in developing FlaQS, with recent ideas in nanofabrication design. As a result, engineering of quantum states of light will be brought to a principally new level. Apart from the compactness, integrability, and broadband operation, FlaQS will be multifunctional and combine generation of quantum states of light with their transformation and frequency conversion. They will enable quantum sensing with subwavelength spatial resolution and subcycle temporal resolution.