Electro-Optical Sampling of Single-Cycle THz Fields with Single-Photon Detectors

Area of Science:

• Quantum optics
• Terahertz (THz) science
• Metrology

Background:

• Electro-optical sampling is a standard method for measuring Terahertz (THz) electric fields using ultrashort optical pulses.
• Current techniques rely on balanced detection, with sensitivity limited by the shot noise of the probe pulse.
• Quantum metrology, utilizing states like NOON states, offers potential for Heisenberg-limited phase estimation and improved sensitivity.

Purpose of the Study:

• To investigate the application of quantum metrology principles to enhance THz electro-optical sampling.
• To explore the use of single-photon detectors and squeezed vacuum states as optical probes for THz field measurement.
• To achieve field sensitivity limited by the quantum statistical properties of the probe state.

Main Methods:

• Implementation of Terahertz (THz) electro-optical sampling utilizing single-photon detectors.
• Employing a weak squeezed vacuum field as the optical probe for enhanced sensitivity.
• Utilizing phase-locked single-photon detectors to measure the optical phase shift induced by THz fields.

Main Results:

• Demonstrated THz electro-optical sampling with single-photon detectors and a squeezed vacuum probe.
• Achieved field sensitivity limited by the statistical properties of the quantum probe state.
• Showcased a novel approach for quantum-enhanced THz sensing.

Conclusions:

• The developed method offers a pathway towards quantum-enhanced Terahertz (THz) sensing.
• This technique surpasses the shot-noise limit of conventional electro-optical sampling.
• Paves the way for future research in quantum metrology for THz applications.