Light across space and phase: creating spin-photon interfaces and probing single-photon emitters

Feng Pan

Department of Materials Science and Engineering, Stanford University

Abstract:

In quantum technologies, room-temperature photonic devices—such as quantum transducers and single-photon light sources—are key building blocks for scalable quantum networks and energy-efficient quantum computing. Yet today’s devices are often limited by rapid decoherence at room temperature, low conversion or emission efficiency, and material-to-material variability that makes performance hard to reproduce. By sculpting light–matter interactions with nanophotonic structures and probing emitters with quantum-optics–based spectroscopy, we can create new routes to robust, high-performance quantum devices.

In this talk, I will present three stories across three material platforms that illustrate this approach, unified by room-temperature operation. First, I will show how engineered symmetry in silicon chiroptical cavities couples the spin of light to electron spin in two-dimensional molybdenum diselenide (MoSe2) monolayers within a Si–MoSe2 heterostructure, enabling efficient room-temperature spin–photon interfaces and a pathway toward scalable hybrid quantum architectures. Second, I will demonstrate how symmetry-controlled nanostructuring of subwavelength-thick nonlinear AlGaAs thin films generates spin-encoded entangled photon pairs at room temperature with efficiencies comparable to those of conventional bulk crystals. Third, I will describe how photon-correlation measurements can disentangle distinct dynamical processes—spanning nanoseconds to milliseconds—in two-dimensional hexagonal boron nitride single-photon emitters that operate at room temperature. Together, these studies highlight how nanophotonic engineering and quantum-optics characterization can accelerate the development of practical room-temperature photonic quantum devices.