Reconstructing subwavelength resolution terahertz holographic images

Area of Science:

• Optics and Photonics
• Metasurfaces
• Terahertz (THz) Imaging

Background:

• Traditional computer-generated holography struggles to achieve high resolution in terahertz (THz) imaging due to pixel sizes exceeding the wavelength.
• Existing methods for THz holographic imaging often lack the necessary resolution for detailed reconstruction.

Purpose of the Study:

• To propose and demonstrate a novel multi-foci metalens model for reconstructing THz holographic images with subwavelength resolution.
• To overcome the resolution limitations of conventional terahertz holographic techniques.

Main Methods:

• Designed dielectric metasurfaces composed of silicon micropillars with spatially variant orientations.
• Utilized a quasi-continuous profile of focal points to act as pixels for holographic image reconstruction.
• Analyzed the impact of focal point size and pitch on imaging quality and pixel resolution.

Main Results:

• Successfully reconstructed THz holographic images with subwavelength resolution using the multi-foci metalens.
• Intensity distribution analysis confirmed the subwavelength resolution of the reconstructed images.
• Demonstrated that the metalens can reconstruct high-resolution target images on its focal plane.

Conclusions:

• The proposed multi-foci metalens design enables THz holographic image reconstruction with subwavelength resolution, surpassing conventional methods.
• This advancement holds significant potential for applications in THz communication, information security, and anti-counterfeiting technologies.