THz near-field spectral encoding imaging using a rainbow metasurface.

Area of Science:

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

Background:

• Terahertz (THz) imaging offers unique capabilities for non-ionizing spectroscopy and imaging.
• Traditional THz imaging techniques can be limited by slow acquisition speeds.
• Metasurfaces provide a powerful platform for manipulating electromagnetic waves, including THz radiation.

Purpose of the Study:

• To demonstrate a novel, fast image acquisition technique in the terahertz range.
• To utilize a metasurface for spectral encoding to achieve rapid 2D image reconstruction.
• To develop a method for efficient 1D data acquisition enabling 2D THz imaging.

Main Methods:

• Fabrication of a metasurface with spatially varying mesh filters exhibiting position-dependent bandpass frequencies (rainbow metasurface).
• Spectral encoding of 1D object information into the transmitted broadband THz pulses.
• Reconstruction of 2D images by measuring transmitted THz pulses through the object and metasurface.

Main Results:

• Successful demonstration of a fast image acquisition technique in the terahertz range.
• Linear mapping of 1D object information into the spectrum of the transmitted THz wave.
• Efficient reconstruction of 2D images using a simplified 1D data acquisition process.

Conclusions:

• The developed rainbow metasurface enables rapid THz image acquisition.
• Spectral encoding via metasurfaces is an effective strategy for enhancing THz imaging speed.
• This technique offers a promising approach for practical 2D THz imaging applications.