arXiv subjects

Clayton D. Moss

Publications and source records attributed to Clayton D. Moss.

4 recordsLinked to original sources

arXiv2025

Ultrafast Faraday Rotation Probe of Chiral Phonon-Polaritons in LiNbO3

Time reversal symmetry breaking motion of chiral phonon-polaritons in LiNbO3 is probed via the ultrafast Faraday effect. By combining a pair of perpendicularly polarized THz pulses with the right relative delay, we create a chiral THz driving field to excite chiral phonon-polaritons. The chiral atomic motion combines with the inverse Faraday effect from the circularly polarized THz pump to induce a magnetic moment field in the nonmagnetic material, LiNbO3. We attempt to quantify the strength of the magnetic field with Faraday rotation probe measurements. The direction of the Faraday signal flips when the input THz pulse is changed from left- to right-circular polarization, and we estimate a strong induced magnetic field strength of ~11 Tesla based on the Faraday rotation.

cond-mat.mes-hall↗

arXiv2023

Wavelength and phase considerations for multi-pulse plasma generation of terahertz

We present a numerical study on plasma generation of THz radiation utilizing multiple light pulses of various wavelengths in an optical scheme that is readily achievable in a tabletop environment. To achieve coherent THz emission it is necessary to carefully consider all the wavelengths involved in a multi-pulse setup. Previous theoretical work has explored ideal waveforms and electric field symmetries for optimal efficiency in generating THz from plasma [Phys. Rev. Lett. 114 183901 (2015)]. In practice such setups are quite delicate and prone to instability. We show that wavelength combinations with lower theoretical efficiency can more easily produce stable THz pulses in a tabletop environment combining readily available near-infrared wavelengths.

physics.optics↗

arXiv2018

Enhancing terahertz generation from a two-color plasma using optical parametric amplifier waste light

We show experimentally that the terahertz (THz) emission of a plasma, generated in air by a two-color laser pulse (containing a near IR frequency and its second harmonic), can be enhanced by the addition of an 800-nm pulse. We observed enhancements of the THz electric field by a factor of up to 30. This provides a widely accessible means for researchers using optical parametric amplifiers (OPA) to increase their THz yields by simply adding the residual pump beam of the OPA to the plasma generating beam. We investigate the dependence of the THz electric field enhancement factor on the powers of the two-color beam as well as the 800-nm enhancement beam. Numerical calculations using the well-known photocurrent model are in excellent agreement with the experimental observations.

physics.plasm-ph↗

arXiv2017

Laser-induced plasma generation of terahertz radiation using three incommensurate wavelengths

We present the generation of THz radiation by focusing ultrafast laser pulses with three incommensurate wavelengths to form a plasma. The three colors include 800 nm and the variable IR signal and idler outputs from an optical parametric amplifier. Stable THz is generated when all three colors are present, with a peak-to-peak field strength of ~200 kV/cm and a relatively broad, smooth spectrum extending out to 6 THz, without any strong dependence on the selection of signal and idler IR wavelengths (in the range from 1300-2000 nm). We confirm that 3 colors are indeed needed, and comment on the polarization characteristics of the generated THz, some of which are challenging to explain with plasma current models that have had success in describing two-color plasma THz generation.

physics.plasm-ph↗