Terahertz Pulse Generation with Binary Phase Control in Nonlinear InAs Metasurface

Area of Science:

• Optics and Photonics
• Materials Science
• Spectroscopy

Background:

• Terahertz (THz) pulse generation is crucial for broadband coherent spectroscopy and imaging.
• Current THz pulses often lack spatial structure, limiting advanced applications.
• Structured beams are increasingly vital for sophisticated spectroscopy.

Purpose of the Study:

• To develop a method for simultaneous generation and spatial structuring of THz beams.
• To explore the use of nonlinear optical metasurfaces with nanoscale emitters for THz beam control.
• To demonstrate a platform for creating binary-phase THz metasurfaces.

Main Methods:

• Fabrication of a nonlinear indium arsenide (InAs) metasurface with nanoscale optical resonators.
• Utilizing optical rectification for THz pulse generation within the resonators.
• Characterization of THz pulse generation efficiency, polarity, and amplitude control.

Main Results:

• The InAs metasurface simultaneously generates and structures THz beams efficiently.
• Optical rectification in InAs resonators is more efficient than in traditional ZnTe crystals.
• Demonstrated control over THz pulse polarity and amplitude, enabling binary-phase metasurfaces.
• Successfully demonstrated an InAs metalens for simultaneous THz pulse generation and focusing.

Conclusions:

• The developed InAs metasurface offers a novel platform for engineered THz beam generation and structuring.
• This technology advances THz spectroscopy and imaging by enabling precise control over spatiotemporal beam properties.
• The findings pave the way for new THz beam engineering applications.