A New Paradigm for Scalable Quantum Optical Circuits—On-Chip Single Photon Source Arrays Integrated with Optically Resonant Metastructure Based Light Manipulating Units

Abstract

Manipulation of single photons generated deterministically from pre-specified sources on-chip to create multiphoton entangled states remains a major goal to be reached in photonic quantum information processing platforms. Notable advances have been made in single photon source performance and demonstrations of photon interference and entanglement based largely upon finding suitable single photon source from an otherwise random ensemble. The lack of scalable on-chip architectures stands as a major obstacle to realizing compact quantum information technologies. In this talk, I will present our proposition [1,2] and continuing efforts [3,4] to realize such a photonic chip built upon a unique class of spatially-ordered arrays of surface-curvature driven mesa-top single quantum dots (MTSQDs) [1,3]. These AlGaAs/InGaAs MTSQDs exhibit spectral uniformity as low as 1.8nm across 5×8 arrays, exhibit pairs of as-grown QDs having emission energy within 200μeV, and single photon purity > 99%. Following a planarization overlayer growth, these buried single photon sources (SPS) provide the essential platform for subsequent lithographic fabrication of emitted photon light manipulating units (LMUs). The LMUs exploit either the well-developed photonic 2D crystal approach or a new approach we introduced [1,2] based upon Mie-like resonances in interacting subwavelength-sized dielectric building block (DBB) based metastructures. The in-plane single Mie-like resonance of the metastructure (the LMU) provides all the needed basic photon manipulation functions to create controlled on-chip interference and entanglement [4]: enhancement of the SPS emission rate (Purcell enhancement), directional emission (local antenna), state-preserving propagation, path bifurcation (beam-splitting), and beam combining. Findings of our combined theoretical analysis, numerical simulations, and experimental studies of such SPS-LMU primitives — the essential building unit for quantum optical circuits — will be presented. The emphasis is on the holistic approach to proofofprinciple demonstration of the needed on-chip multifunctional system with its built-in trade-offs rather than the best of any individual light manipulation function. The work is supported by the US Army Research Office (W911NF1910025) and the Air Force Office of Scientific Research (FA9550-17-1-0353). 1. Jiefei Zhang et al., Jour. App. Phys. 120, 243103 (2016) 2. Swarnabha Chattaraj et al., Jour. Opt. Soc. America B. 33, 2414(2016) 3. Jiefei Zhang, et al., App. Phys. Lett 114, 071102 (2019) 4. Swarnabha Chattaraj et al., IEEE Jour. Quant. Elec. 56, 1 (2019)