Carbon nanotubes for polarization sensitive terahertz plasmonic interferometry

Area of Science:

• Condensed Matter Physics
• Nanotechnology
• Terahertz Science

Background:

• Carbon nanotubes (CNTs) exhibit unique electronic properties.
• Photovoltaic effects in nanostructures are crucial for optoelectronic devices.
• Terahertz (THz) radiation offers novel sensing and imaging capabilities.

Purpose of the Study:

• To investigate the helicity-sensitive photovoltaic response of CNT field-effect transistors (FETs) to THz radiation.
• To elucidate the underlying physical mechanism of this observed phenomenon.
• To explore potential applications in plasmonic interferometry.

Main Methods:

• Fabrication of CNT-based field-effect transistors.
• Measurement of the photovoltaic response under circularly polarized THz radiation.
• Analysis of the rectified voltage dependence on helicity and phase.

Main Results:

• A distinct difference in rectified voltage was observed for clockwise and anticlockwise circularly polarized THz radiation.
• This helicity sensitivity is attributed to plasma wave interference within the transistor channel.
• The phenomenon was confirmed as universal across different dimensional systems and single-particle spectra.

Conclusions:

• The helicity-sensitive photovoltaic response in CNT-FETs is a fingerprint of plasma wave interference.
• The magnitude of this response is characteristic of the plasma wave decay length.
• This finding opens new possibilities for plasmonic interferometry and THz sensing.