All-optical hybrid metasurfaces for ultrafast computational spectrometer and single-pixel imaging

Area of Science:

• Optics and Photonics
• Metamaterials
• Terahertz Technology

Background:

• Terahertz (THz) spectrum offers potential for sensing and imaging.
• Conventional THz spectrometers face challenges in miniaturization, speed, and cost due to mechanical components.

Purpose of the Study:

• To develop an active hybrid metasurface for THz computational spectroscopy and single-pixel imaging.
• To overcome limitations of traditional THz spectrometers.

Main Methods:

• Utilized a dispersion-engineered metasurface with quasi-bound states in the continuum for dense, high-Q resonances.
• Employed all-optical excitation of integrated silicon patches for dynamic modulation.
• Implemented temporally modulated metasurfaces for incoherent single-pixel detection and spectral reconstruction.
• Demonstrated a pixelated metasurface array for THz single-pixel imaging.

Main Results:

• Achieved nanosecond-scale spectral reconstruction with 0.03 THz resolution over a 0.25 THz bandwidth.
• Demonstrated ultrafast THz single-pixel imaging with a 3x3 pixel array.
• The metasurface functions as a low-correlation, ultrafast spectral/spatial light modulator.

Conclusions:

• The CMOS-compatible, circuit-free strategy enables compact, high-resolution, and ultrafast THz spectroscopy and imaging.
• This approach offers a scalable pathway for next-generation THz photonic devices.