Illuminating Quantum Phenomena in 2D Materials: The Power of Optical Spectroscopy

Abstract 2D materials, characterized by atomically thin structures and extraordinary electronic properties, offer fertile ground for exploring quantum phenomena governed by reduced dimensionality, quantum confinement, and strong many‐body interactions. Understanding these quantum effects‐such as quantum tunneling, plasmonic excitations, and exciton dynamics is crucial for enabling future quantum technologies. Optical spectroscopy, due to its non‐invasive nature, ultrahigh spatial, and temporal resolution, and exceptional sensitivity to electronic, vibrational, and structural states, has emerged as an indispensable approach for investigating these phenomena. Despite extensive theoretical predictions, a systematic experimental review explicitly connecting quantum properties in 2D materials to advanced optical spectroscopic techniques remains lacking. This review addresses this gap by describing the experimental manifestations of quantum properties and their characterization using cutting‐edge optical tools, including near‐field scanning optical microscopy (NSOM), pump–probe spectroscopy, advanced Raman‐based methods (such as coherent anti‐Stokes Raman scattering (CARS) and time‐resolved Raman (TRR)), and optical frequency comb spectroscopy. Emphasis is placed on the distinct capabilities of each technique for elucidating ultrafast carrier dynamics, phonon coherence, interlayer tunneling, and exciton relaxation processes. By linking individual quantum phenomenon to appropriate spectroscopic approaches, this review shines a light on optical spectroscopy in advancing both fundamental understanding and technological development of next‐generation quantum materials.