Quantum Light Nano-Imaging

Entanglement and quantum correlations are central to the physics of quantum materials, yet they have remained notoriously difficult to probe experimentally. Probing these phenomena in solids requires quantum optical probes that operate at the native length and time scales of material excitations, below the diffraction limit of light. Developing the requisite tools has previously been infeasible due to the weak intensities of state-of-the-art quantum light sources and the inefficiency of light coupling in near-field light-matter interactions. In this work, we address these challenges and report the development of a quantum light scattering-type scanning near-field optical microscope (q-SNOM) that enables quantum-optical studies of solid-state systems with nanoscale spatial resolution. As a first demonstration, we image in real space the self-interference of single hybrid light-matter quasiparticles in a prototypical van der Waals semiconductor MoS2, providing a direct nanoscale visualization of the wave-particle duality. We also introduce a polaritonic time-of-flight metrology that exploits the temporal correlations among entangled photons to observe the quasiparticle propagation dynamics with femtosecond resolution. This work establishes a new experimental paradigm for nanoscale exploration and control of quantum effects in materials.