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The rapidly emerging field of 2D magnetic materials has garnered significant attention due to its fascinating physical properties and wide‐ranging potential applications. This review highlights the importance of magneto‐optical interactions as a crucial tool for both studying and modulating 2D magnets. It offers a comprehensive survey of current research concerning magneto‐optical interactions in 2D magnetic materials, encompassing the magneto‐optical Kerr effect, reflection magnetic circular dichroism, second‐harmonic generation, photoluminescence, inelastic light scattering, and time‐resolved spectroscopy. This review discusses how these techniques provide insights into the properties of 2D magnets, enabling exploration of magnetic phase transitions, lattice alterations, spin dynamics, as well as their responses to external fields. Moreover, it emphasizes the modulation of magnetic properties by photo‐stimulation and offers a brief outlook on this swiftly developing field. [ABSTRACT FROM AUTHOR]

The measurements of interlayer vibrations in multilayer graphene (MLG) have triggered a huge effort to understand phonons, electron–electron, electron–phonon, magneto–phonon interactions and the effect of layer number, stacking sequences, and layer orientations on the Raman spectroscopy of MLG. Here, we provide a review on the optical probe of interlayer vibrations, comprising the shear (C) and layer breathing (LB) modes. At first, we discuss different symmetries of MLGs in AB, ABC, and twisted stacking with an example of trilayer graphene, which dramatically influence the observations of interlayer vibrations. Then a brief description about the physical origins of the C and LB modes is introduced. Finally, two ways are elucidated to probe the interlayer modes in detail. The C and LB modes can be directly probed in the ultralow‐wavenumber Raman spectroscopy with special configurations, as depicted by the Raman spectra in MLG with diverse stacking orders. On the other hand, the LB modes can also be derived from the two‐phonon overtones in doubly resonant Raman spectra. These approaches can be extended to the other two‐dimensional layered materials, which pave the way to measure the interlayer coupling from experiments and thus greatly benefit the future research studies on their fundamental physics and potential applications. Copyright © 2017 JohnWiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The quantum confinement in atomic scale and the presence of interlayer coupling in multilayer make the electronic and optical properties of 2D materials (2DMs) be dependent on the layer number ( N) from monolayer to multilayer. Optical properties of 2DMs have been widely probed by several optical techniques, such as optical contrast, Rayleigh scattering, Raman spectroscopy, optical absorption, photoluminescence, and second harmonic generation. Here, it is reviewed how optical properties of several typical 2DMs (e.g., monolayer and multilayer graphenes, transition metal dichalcogenides) probed by these optical techniques significantly depend on N. Further, it has been demonstrated how these optical techniques service as fast and nondestructive approaches for N counting or thickness determination of these typical 2DM flakes. The corresponding approaches can be extended to the whole 2DM family produced by micromechanical exfoliations, chemical-vapor-deposition growth, or transfer processes on various substrates, which bridges the gap between the characterization and international standardization for thickness determination of 2DM flakes. [ABSTRACT FROM AUTHOR]