Terahertz Magnetic Modulator based on Magnetically-Clustered Nanoparticles

TL;DR

This paper demonstrates a terahertz magnetic modulator using magnetically-clustered nanoparticles in ferrofluid, achieving significant polarization modulation through external magnetic fields, advancing terahertz device technology.

Contribution

It introduces a novel terahertz magnetic modulator based on magnetically-clustered nanoparticles, with experimental validation of high modulation depth.

Findings

Achieved 66% modulation depth at 35 mT magnetic field.

Demonstrated polarization-sensitive modulation at terahertz frequencies.

Validated the concept as a fundamental solution for terahertz magnetic modulators.

Abstract

Random orientation of liquid-suspended magnetic nanoparticles (Ferrofluid) gives rise to zero net magnetic orientation. An external magnetic field tends to align them into clusters, leading to a strong linear dichroism on a propagating wave. Using 10 nm-sized Fe3O4, we experimentally realize a polarization-sensitive magnetic modulator operating at terahertz wavelengths. We reached a modulation depth of 66% using a field of 35 mT. The proposed concept offers a solution towards fundamental terahertz magnetic modulators.