Edge Detection Imaging by Quasi-Bound States in the Continuum

Area of Science:

• Photonics and Optical Engineering
• Metasurface Technology
• Analog Computing

Background:

• Optical metasurfaces enable subwavelength analog computing and image processing with high speed and low power consumption.
• Engineered angular dispersion is typically used for spatial differentiation in metasurfaces.
• Quasi-bound states in the continuum (quasi-BICs) offer customizable optical resonances with high Q-factors and field confinement.

Purpose of the Study:

• To explore the unexplored potential of quasi-BICs in optical image processing.
• To demonstrate edge detection imaging using quasi-BIC metasurfaces.
• To develop ultracompact, low-power optical computing devices.

Main Methods:

• Designed an all-dielectric metasurface composed of four nanodisks per unit cell.
• Engineered a polarization-independent quasi-BIC through structural perturbations.
• Achieved simultaneous control over Q-factor and angular dispersion for isotropic 2D spatial differentiation.

Main Results:

• Successfully demonstrated efficient and high-quality edge detection imaging using the fabricated quasi-BIC metasurfaces.
• Validated the performance under various polarization conditions.
• Showcased the capability for isotropic two-dimensional spatial differentiation crucial for edge detection.

Conclusions:

• Quasi-BIC metasurfaces are effective for edge detection imaging.
• This work illuminates the mechanisms of edge detection with quasi-BIC metasurfaces.
• Opens new avenues for ultracompact, low-power optical computing devices.