Dual-Mode Electro-Optic Modulation Based on BaTiO 3 Guided-Mode Resonances Assisted by Spatial Filtering

This is the authors' abstract. We don't add key points for this paper.

Liquid crystal spatial light modulators suffer from slow response, while conventional electro-optic (EO) thin-film devices exhibit limited modulation depth, hindering high-speed programmable optical systems. Here, we numerically propose a dual-mode EO spatial modulation scheme enabled by barium titanate guided-mode resonance (BaTiO3-GMR) combined with spatial filtering. A SiN photonic crystal structure integrated with a continuous BaTiO3 thin film uses GMR to convert weak electrically induced refractive index perturbations into pronounced complex reflection changes. To overcome the intrinsic amplitude-phase (AP) coupling of single resonant pixels, a two-pixel coherent field synthesis strategy expands the accessible complex field state space, enabling programmable joint AP encoding. Amplitude-type and phase-type trajectories are then selected as two representative constrained modes via 4f spatial-filtering readout. The numerical model yields a broad range near amplitude-only modulation (0 to 0.668) and phase modulation exceeding 2.443 rad. Simulations using MNIST handwritten digits further evaluate 2D amplitude and phase pattern reconstruction. These results establish a simulation-based proof of concept for dual-mode amplitude and phase modulation and provide a numerical basis for future development of programmable optical modulation systems.