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

Abstract

Electro-optical sampling of Terahertz fields with ultrashort pulsed probes is a well-established approach for directly measuring the electric field of THz radiation. This technique usually relies on balanced detection to record the optical phase shift brought by THz-induced birefringence. The sensitivity of electro-optical sampling is, therefore, limited by the shot noise of the probe pulse, and improvements could be achieved using quantum metrology approaches using, e.g., NOON states for Heisenberg-limited phase estimation. We report on our experiments on THz electro-optical sampling using single-photon detectors and a weak squeezed vacuum field as the optical probe. Our approach achieves field sensitivity limited by the probe state statistical properties using phase-locked single-photon detectors and paves the way for further studies targeting quantum-enhanced THz sensing.

Modeling and Analysis of a Long-Range Target Localization Problem Based on an XS Anode Single-Photon Detector

“…Since photon-counting imaging detectors can detect weak signals, they can be applied to quantum communication, sensing and metrology [1]. Moreover, photon-counting imaging detectors can be used to measure the electric field of terahertz radiation [2], detect the composition of dark matter [3] and carry out low-light-level time-resolved fluorescence microscopy [4][5][6][7][8][9]. In order to improve the efficiency and quality of the detection, researchers are constantly improving and refining the detectors [10].…”