Broadband terahertz holography using isotropic VO₂ metasurfaces.

Area of Science:

• Metamaterials
• Optics and Photonics
• Condensed Matter Physics

Background:

• Vanadium dioxide (VO₂) possesses unique phase transition properties crucial for dynamic electromagnetic wave manipulation.
• Metasurfaces offer advanced control over electromagnetic waves, enabling applications like holography.
• Terahertz (THz) wave applications require efficient and tunable holographic techniques.

Purpose of the Study:

• To design and demonstrate a novel bilayer isotropic metasurface for broadband terahertz holography.
• To leverage the insulating-to-metallic phase transition of VO₂ for tunable holographic functionalities.
• To explore frequency-multiplexed holography using the distinct states of VO₂.

Main Methods:

• Fabrication of a bilayer metasurface incorporating vanadium dioxide (VO₂) antennas.
• Characterization of terahertz wave interaction with the metasurface in both insulating and metallic VO₂ states.
• Analysis of holographic pattern generation and frequency response across a broad bandwidth.

Main Results:

• The proposed metasurface achieves broadband holography for terahertz waves, operating from 1.0-2.1 THz.
• Independent holographic generation is demonstrated for both metallic (1.2 THz) and insulating (1.9 THz) VO₂ states.
• Frequency doubling is observed in the insulating state, enabling distinct holographic functionalities.

Conclusions:

• The developed VO₂-based bilayer metasurface offers a promising platform for broadband and tunable terahertz holography.
• The independent control over holographic generation in different VO₂ states opens possibilities for frequency-multiplexed holographic displays and information encryption.
• This research advances the capabilities of metasurfaces for advanced terahertz wave manipulation and applications.