Terahertz rectification in ring-shaped quantum barriers

Area of Science:

• Quantum mechanics
• Condensed matter physics
• Optoelectronics

Background:

• Quantum tunneling is a fundamental phenomenon where particles pass through potential barriers.
• Controlling tunneling currents typically involves applying voltage, limiting ultrafast applications.
• Existing methods lack precise spatial and temporal control over tunneling dynamics.

Purpose of the Study:

• To investigate optical control of quantum tunneling currents in closed-loop geometries.
• To explore the manipulation of ultrafast tunneling electrons using electromagnetic pulses.
• To enable full-wave rectification of terahertz pulses via quantum tunneling.

Main Methods:

• Fabrication of closed loops of tunneling barriers.
• Exposure of these loops to controlled electromagnetic pulses (terahertz range).
• Analysis of how eddy currents and local potential changes affect tunneling currents.

Main Results:

• Demonstrated spatiotemporal modulation of local potentials by induced eddy currents.
• Observed critical dependence of total tunneling current on loop symmetry and incident field polarization.
• Achieved full-wave rectification of terahertz pulses through controlled quantum tunneling.

Conclusions:

• Introduced a novel platform combining global geometry and local optical control for quantum phenomena.
• Established a method for manipulating ultrafast tunneling electrons with high precision.
• Highlighted potential applications in ultrafast optoelectronics, energy harvesting, and quantum devices.