A solid-state quantum light source with spin angular momentum

Jennifer Dionne, Associate Professor of Materials Science and Engineering, Senior Fellow at the Precourt Institute for Energy, and Associate Professor, by Courtesy, of Radiology

Daniel Congreve, Assistant Professor of Electrical Engineering

Fang Liu, Proteomics Mass Spectrometry Staff Scientist, Mass Spectrometry Center

The classical nature of light is described by continuous oscillations of electric and magnetic fields and holds true for phenomena such as reflection, refraction, and interference. The quantum nature of light includes superposition, entanglement, and quantized energy levels. Utilizing the quantum nature of light (including generation single photons and photon pairs) underpins many quantum applications, including secure and robust quantum communication, quantum-enhanced sensing and spectroscopy, and quantum optics.¹

Existing quantum sources of single photons and correlated photon pairs face two key limitations. First, they are not readily capable of integrating spin angular momentum, a crucial parameter for high-fidelity quantum processing. Second, they are not readily integrated in quantum circuitry platforms that are compatible with complementary metal–oxide–semiconductor technology for quantum state transduction and operation. For example, conventional approaches for generating single photons rely on coherent control of two-level systems (e.g. single atoms or molecules). Recently, solid-state systems, including defects in 2D materials and atom-like quantum dots, have been demonstrated to generate high-purity and indistinguishable single photons, yet without spin angular momentum. In parallel, spontaneous parametric down-conversion (SPDC) is commonly used to generate correlated photon pairs. SPDC relies on parametric amplification of quantum vacuum fluctuation to annihilate one input photon and give rise to a pair of signal and idler photons. SPDC is highly contingent on the second-order susceptibility and phase-matching in a nonlinear medium, but currently requires centimeter-thick nonlinear crystals such as beta barium borate (BBO) and periodically poled potassium titanyl phosphate (PPKTP).

Our proposal will combine state-of-the-art high-Q metasurface design and fabrication with advanced TMDC and perovskite materials preparation and characterization. We will fabricate high-Q chiral metasurfaces (Specific Aim 1) and integrate them with perovskite thin films for chiral single-photon emission (Specific Aim 2) and TMDC monolayers for chiral entangled-photon pair generation (Specific Aim 3). The quantum nature of light emission will be interrogated using our home-built chiral photon-correlation characterization methods. Through our integrated computational design, fabrication, and experimental characterization, we will create a solid-state device that enables bright single-photon emission and high SPDC efficiency, while simultaneously controlling the spin angular momentum of quantum light.