Fig. 1. Hybrid structure consisting of a one-dimensional gold grating and a monolayer tungsten disulfide and its reflection spectrum and field distribution. (a) Schematic of hybrid structure with gold grating and monolayer tungsten disulfide; (b) reflection spectra of gold grating structure and gold grating/monolayer tungsten disulfide_{hybrid structure with grating pitch p=400 nm, width l=300 nm, and height h=95 nm. Inset shows reflection spectrum of a monolayer tungsten disulfide; (c) distribution of electric field |E/E0| in gold grating structure at reflection dip wavelength of 620 nm; (d) distribution of electric field |E/E0| of gold grating/monolayer tungsten disulfide hybrid structure at reflection peak wavelength of 620 nm}

Fig. 2. Relationship between reflection spectrum of gold grating and grating pitches. (a) Reflection spectra of gold grating structures with different pitches p; (b) reflection spectra of gold grating/monolayer tungsten disulfide hybrid structures with different p (solid lines) and reflection spectra fitted by temporal coupled-mode theory (dashed lines). Other parameters are set as l=300 nm and h=95 nm

Fig. 3. Relationship between reflection spectrum of gold grating and grating widths. (a) Reflection spectra of gold grating structures with different widths l; (b) reflection spectra of gold grating/monolayer tungsten disulfide hybrid structures with different l (solid lines) and theoretically fitted reflection spectra (dashed lines). Other parameters are set as p=400 nm and h=95 nm

Fig. 4. Relationship between reflection spectrum of gold grating and grating heights. (a) Reflection spectra of gold grating structures with different heights h; (b) reflection spectra of gold grating/monolayer tungsten disulfide hybrid structures with different h (solid lines)and theoretically fitted reflection spectra (dashed lines). Other parameters are set as p=400 nm and l=300 nm

Fig. 5. Parameters fitted by temporal coupled-mode theory. Theoretically fitted (a) plasmonic resonance frequency ωa, (b) coupling strength g, (c) decay rate γ1, and (d) decay rate γ2 varying with gold grating heights h

Fig. 6. Strong coupling between surface plasmons in gold grating and excitons in monolayer tungsten disulfide. (a) Splitting energy UP (dots above) and LP (dots below) branches in coupling between surface plasmons and excitons in gold grating/monolayer tungsten disulfide hybrid structure varying with detuning δ. Solid curves denote fitting results by coupled oscillator model; (b) fractions of surface plasmons and excitons in UP branch varying with detuning δ

Fig. 7. Reflection spectra of gold grating/monolayer tungsten disulfide hybrid structure with different environmental refractive indices when p, l, and h of gold grating are 400, 300, and 105 nm, respectively. Inset shows relationship between reflection dip wavelength difference Δλ and refractive index n. Dots denote simulation results and solid line denotes fitting result

Table 1. Related parameters of dielectric constant of monolayer tungsten disulfide