Acousto-optic Device Meta Structure Diffraction Efficiency

The patent uses a composite structure consisting of a natural elastic medium combined with a meta-structure layer. The elastic medium provides acoustic wave propagation, while the meta-structure layer with periodic patterns enhances light modulation. This composite approach achieves high acousto-optic conversion efficiency by combining the advantages of natural materials with engineered periodic structures that create strong diffraction effects.

The patent changes the optical parameters of the medium by introducing a meta-structure layer with specific periodic patterns. The periodicity of the meta-structure is designed to match the acoustic wavelength, creating a phase grating effect that significantly enhances diffraction efficiency. This parameter optimization allows the device to achieve wide diffraction angle ranges and high conversion efficiency simultaneously.

The composite structure of elastic medium plus meta-structure layer enables the device to achieve wide diffraction angle ranges. The meta-structure's periodic patterns are designed to work with the acoustic waves in the elastic medium, creating multiple diffraction orders and expanding the angular range of diffracted light while maintaining structural simplicity.

The patent introduces a periodic meta-structure layer that adds a spatial dimension of periodicity to the system. This periodic structure creates a phase grating effect that diffracts light in multiple directions, effectively expanding the diffraction angle range from a single direction to a wide angular spectrum, thereby enhancing the device's versatility for scanning and modulation applications.

The meta-structure layer is designed as a periodic patterned structure that can be fabricated using standard microfabrication techniques. The periodic patterns are relatively simple geometric shapes that repeat throughout the layer, making the manufacturing process straightforward despite the enhanced functionality. This approach achieves high conversion efficiency without requiring complex device architecture.

The patent optimizes specific parameters of the meta-structure, such as pattern periodicity, duty cycle, and layer thickness, to achieve maximum diffraction efficiency. By carefully selecting these parameters to match the acoustic wavelength and optical wavelength, the device achieves high conversion efficiency with a relatively simple periodic structure, avoiding the need for complex multi-layer or asymmetric designs.