Figure 2
High refractive index enabled giant OPL in ultra-thin film. (a and b) Schematic plots of multiple reflections at the interfaces of ultra-thin 2D materials. High refractive index leads to a large reflection coefficient. Light is reflected many times inside the material and leads to a highly enhanced light path, indicated as (a). For low refractive index material, the light path is much less enhanced because of the small reflection coefficient, indicated as (b). (c) Simulated OPL values for light reflected from 2D material (0.67 nm in thickness) with different indices on a SiO2 (275 nm)/Si substrate (solid line) and SiO2 substrate with infinite thickness (dashed line). The calculated OPLs of 0.67 nm Au, 0.67 nm SiO2, 1L (0.34 nm) graphene, and 1L (0.67 nm) MoS2 are represented by markers. (d) Simulated OPL values for 1L, 2L, 3L, and 4L MoS2 and graphene on SiO2 (275 nm)/Si substrate, respectively. The wavelength used in the simulations was 535 nm.
