Fig. 1. Schematic diagrams of liquid-containing membrane microtank structure and radiation transfer. (a) Schematic diagram of the geometric parameters of the micro-groove structure of the liquid-containing film; (b) establishment of the coordinate system

Fig. 2. Computational domain and boundary conditions

Fig. 3. Comparison of the results of the FDTD method calculations with the data from literature Ref. [23-24]. (a) Comparison of the FDTD method with the method in Ref. [23]; (b) comparison of the FDTD method with the method in Ref. [24]

Fig. 4. Reflectance and mean value of two polarization components for several working conditions (set D=10 μm, h=2 μm). (a) θ=60°, θ_i=0°; (b) θ=120°, θ_i=0°; (c) θ=60°, θ_i=20°; (d) θ=120°, θ_i=20°

Fig. 5. Comparison of theoretical liquid film curves and circular approximation treatment reflectance for several operating conditions (set D=10 μm, θ_i=0°). (a) θ=60°, h=2 μm; (b) θ=120°, h=2 μm; (c) θ=60°, h=3 μm; (d) θ=120°, h=3 μm

Fig. 6. Reflectance of rectangular channel at vertical incidence for different liquid film thicknesses. (a) θ=60°; (b) θ=120°

Fig. 7. Directional reflectance distribution of different liquid film thicknesses at different wavelengths. (a) λ=2 μm; (b) λ=4 μm

Fig. 8. Maps of the distribution of electric and magnetic fields in the plane of incidence when vertically incident. (a) Electric field distribution map of liquid-free film; (b) magnetic field distribution map of liquid-free film; (c) electric field distribution map at h=3 μm; (d) magnetic field distribution map at h=3 μm

Fig. 9. Reflectance variation curves for different channel widths at vertical incidence. (a) h=2 μm; (b) h=3 μm

Fig. 10. Directional reflectance distribution of different channel widths at different wavelengths. (a) λ=2 μm; (b) λ=4 μm

Fig. 11. Reflectance distribution at different incidence angles. (a) θ=60°; (b) θ=120°

Fig. 12. Distribution of directional reflectance at different wavelengths and angles of incidence. (a) λ=2 μm; (b) λ=4 μm

Fig. 13. Maps of the distribution of electric and magnetic fields in the plane of incidence when inclined to incident. (a) Electric field distribution map at h=3 μm; (b) magnetic field distribution map at h=3 μm

Fig. 14. Liquid film curves in the two cases obtained by numerical solution. (a) Wetting; (b) non-wetting

Fig. 15. Reflectance distribution at different dip angles for vertical incidence. (a) h=2 μm; (b) h=4 μm

Fig. 16. Directional reflectance distribution of different infiltration angles at different wavelengths. (a) λ=2 μm; (b) λ=4 μm