Related Experiment Video
Updated: Oct 29, 2025

A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference
Published on: September 5, 2019
Correlation polarimeter-interferometer in the DIII-D tokamak
Jie Chen1, David Brower1, Weixing Ding1
1University of California Los Angeles, Los Angeles, California 90095, USA.
Abstract:
A correlation polarimeter-interferometer system has been developed for the DIII-D tokamak to detect small amplitude magnetic and density fluctuations. Two collinear, frequency-offset (5-15 MHz), orthogonally polarized (right- and left-handed, circularly polarized) electromagnetic waves at 650 GHz probing the plasma are used to detect the Faraday effect. A third, linearly polarized, electromagnetic wave serves as the local-oscillator to provide a measure of the line-averaged density. Correlation polarimetric measurement is accomplished by correlating the Faraday effect measured along the same line of sight using two independent detectors, whereas simultaneous correlation interferometric measurement is realized by correlating the line-averaged density measured at two different intermediate frequencies. The noise floor of the correlation polarimeter-interferometer has been demonstrated to be more than one order of magnitude lower than that of a standard polarimeter-interferometer measurement. Line-averaged correlation polarimetric-interferometric measurements in DIII-D H-mode plasmas show broadband (up to 750 kHz) magnetic and density fluctuations with amplitudes as low as 0.03Gauss/kHz and 4×1013m-3/kHz, respectively.
Related Concept Videos
Inductively Coupled Plasma-Mass Spectrometry (ICP-MS): Interferences
Induced Electric Dipoles
Since the absolute value of potential energy holds no physical meaning, its zero value can be chosen as per...
IR Spectrometers
IR Spectrum Peak Intensity: Dipole Moment
Electric Dipoles and Dipole Moment
Theoretically, studying electric dipoles leads to understanding why the resultant electric forces around us are weak. Since electric forces are strong, remnant net charges are rare. Hence, the interaction between dipoles helps us understand electrical interactions in...
Dielectric Polarization in a Capacitor

