Fig. 1. Schematic diagrams of 2D material-micro/nano-photonic cavity coupling systems. (a) Monolayer 2D material; (b) multilayer 2D material; (c) twist angle and Moiré fringe; (d) DBR microcavity; (e) grating cavity; (f) defect photonic crystal

Fig. 2. Interactions of exciton-photon. (a) Temperature-dependent photoluminescence (PL) spectra^[52]; (b) multi-peak Lorentzian fitting of the PL spectra at temperature of 95 K^[52]; (c) interaction strengths obtained experimentally (dot) and theoretically (solid line) at different temperatures^[52]; (d) schematic diagram of the valley-polarized exciton-polaritons of TMDs in a microcavity^[53]; (e) dispersion relation of exciton-polaritons^[53]; (f) structure of the nanobeam cavity and the electric field distribution of cavity mode M1^[54]; (g) magneto PL spectra recorded at a low excitation power and the intensity of exciton-photon coupling given by the relationship between the linewidth and the detuning^[54]

Fig. 3. Interactions of exciton-phonon. (a) Temperature-dependent cavity-coupled PL spectra of monolayer WSe₂, from top to bottom is 320, 240, 160 K, and 80 K, respectively^[62]; (b) calculated vibrational modes of the nanobeam cavity^[63]; (c) T^N dependence of gX0,2LA in cavities^[63]; (d) schematic diagram of the exciton-phonon-phonon coupling^[63]

Fig. 4. Interactions of exciton-magnon. (a) Relationship between the relative spin alignment and the exciton resonance energy in CrSBr^[69]; (b) reflectance and transient reflectance spectra of CrSBr^[67]; (c) schematic diagrams of the bright (B) and dark (D) modes^[69]; (d) magnon dispersion of CrSBr obtained by Fourier transform of the ultrafast spectral data^[69]; (e) calculated exciton resonance energy shift during the precession of the optical and acoustic magnon modes^[69]

Fig. 5. Electric field control of 2D materials. (a) Optical image of WSe₂ device^[72]; (b) schematic diagram of a monolayer WSe₂ device^[72]; (c) PL spectrum of monolayer WSe₂^[72]; (d) schematic diagram of a bilayer MoS₂ device encapsulated in hBN^[73]; (e) schematic diagram of the coexistence of IXs and phonons^[73]; (f) schematic diagram of the variation in emission energies of IX₁ and IX₂ from the PL spectrum of bilayer MoS₂ with electric field, illustration is schematic diagram of IXs configurations in real space^[73]; (g) schematic diagram of the first-order derivative for Raman intensity with respect to phonon frequency^[73]

Fig. 6. Magnetic field control of 2D materials. (a) Reflection spectrum of monolayer WS₂ at 0 T and 4 K, along with the normalized reflection spectra of A and B excitons under σ+ polarized light^[74]; (b) variation in the magneto-optical Kerr rotation angle with magnetic field for CrI₃ with different layer numbers, illustration is structural diagram of CrI₃ and its Ising-type spin orientation^[65]; (c) schematic diagram of the CrSBr crystal and its magnetic structure^[75]; (d) PL spectra of bilayer CrSBr with the magnetic field direction along the b-axis^[75]; (e) PL spectra of bilayer CrSBr with the magnetic field direction along the c-axis^[75]

Fig. 7. Optimization and regulation of micro-nano photonic cavities. (a) Resonant spectra of microcavities with various shifts of air rods at defects and their SEM pictures, illustration is the resonant spectrum of the microcavity measured over a wide wavelength range with 0.15a shift^[76]; (b) variation in estimated Q/V values with shift of air rods^[76]; (c) schematic diagram of monolayer WSe₂ integrated with L3-type photonic crystal^[77]; (d) schematic diagram of bilayer MoS₂/WSe₂ heterobilayers integrated with photonic crystal^[78]

Fig. 8. Schematic diagrams of multi-cavity coupling. (a) Theoretical curves of the energies and Q values of the split fundamental modes of parallel L3 cavities coupled along different directions^[81]; (b) schematic diagram of the homoatomic PMs^[82]; (c) schematic diagram of the heteroatomic PMs^[82]; (d) bare frequency, frequency-dependent coupling strength, and eigenfrequency of the PMs when homoatomic PMs is coupled^[82]; (e) bare frequency,eigenfrequency at the diabolical point between weak and strong coupling, and eigenfrequency of the PMs when heteroatomic PMs is coupled^[82]