Fig. 1. Broadening of reflection bandwidth: (a) reflectivity of different layers of PC/PMMA multilayer film; (b) reflectance spectra of periodic films with different thicknesses.

Fig. 2. Superimposing of film stacks at different passband positions.

Fig. 3. Three-passband multilayer film suitable for plant photosynthesis.

Fig. 4. Spectrum of the double-passband polymer multilayer optical film.

Fig. 5. Multi-passband filter film applied to the photovoltaic agricultural system: (a) solar radiation and spectral response of crystalline silicon cells; (b) biaxial tracking photovoltaic agricultural system; (c) spectra required for plant photosynthesis.