Spatial sampling of terahertz fields with sub-wavelength accuracy via probe-beam encoding.

Area of Science:

• Optics and Photonics
• Terahertz (THz) Science and Technology
• Computational Imaging

Background:

• Characterizing terahertz (THz) fields spatially is crucial for various applications.
• Existing methods often require specialized THz devices or complex optical setups with synchronized beams.

Purpose of the Study:

• To develop a simplified computational sampling approach for probing THz fields.
• To achieve high-resolution spatial characterization of THz fields without specialized THz modulators.

Main Methods:

• Spatially encoding an 800-nm near-infrared (NIR) probe beam using an optical spatial light modulator (SLM).
• Probing THz fields with a single-pixel camera.
• Utilizing computational algorithms to reconstruct THz field distributions.

Main Results:

• Successfully measured 128x128 THz field distributions.
• Achieved a transverse spatial resolution of 62 μm, which is sub-wavelength (15 times smaller than the 940 μm THz wavelength).
• Demonstrated a system that does not require dedicated THz devices, semiconductors, or nanofilms.

Conclusions:

• The developed method offers a simple, non-invasive approach for THz field characterization.
• The sub-wavelength resolution enables potential applications in biomedical sensing and industrial inspection.
• This technique simplifies THz imaging by avoiding complex and specialized equipment.