PhoG · Sub-Poissonian Photon Gun by Coherent Diffusive Photonics

The goal of the project is to deliver deterministic compact sources of highly non-classical states, from sub-Poissonian light to multi-mode entanglement, all utilizing a solitary technological platform. The project will build their working prototypes and develop the technology foundation for applications of these sources in an advanced optical imaging and metrology. The proposed sources will be based on a novel paradigm in photonic devices: diffusive coherent photonics operating with dissipatively coupled photonic circuits. The project will demonstrate that light can flow diffusively retaining coherence and even entanglement, be effectively equalized, distributed in a controlled way or even localized in perfectly periodic structures by means of dissipative coupling. Such unique light propagation regimes will be realized with the help of a photonic analogue of a tight-binding lattice using coupled waveguide networks in linear and non-linear glass materials. These coherent photonic devices will be fabricated by ultrafast laser inscription, and the dissipative coupling implemented by mutually coupling each pair of waveguides in the chain to a linear arrangement of waveguides. Efficient quantum diagnostics methods will be developed to verify the source characteristics and to assess their technological readiness. We expect coherent diffusive photonic devices to find applications in photonic networks and in a range of metrology tasks, potentially also for simulations of complex quantum dynamics. The project goal thus is: 1) to implement a family of compact sub-Poissonian photon guns, capable of robust generation of mesoscopic non-classical and entangled states; 2) to perform a feasibility study of their applications in entanglement-enhanced imaging and atomic clocks aiming at the 2 times better clock frequency stability.