arXiv subjects

Jordan M. Adams

Publications and source records attributed to Jordan M. Adams.

5 recordsLinked to original sources

arXiv2026

Spatiotemporal representation of a two-vortex reconnection as a single rotating vortex

Reconnections and rotations of lines are dual descriptions of the same saddle-shaped spacetime surface. We show that a reconnection between two line occurring over time is a single line that rotates over space progression. Both rotating lines and reconnections possess the same saddle shape sheet geometry in four-dimensional space-time, with different orientations. Cyclic precessing lines occurring over time are arrays of reconnections occurring spatially. We show that a magnetic reconnection occurring over time can be seen as a single continuous line vector potential rotating spatially, where the full evolution traces a saddle shape surface. Finally, we show that a single tilted spatiotemporal optical vortex precesses with spatial progression, and as a result can be seen as two vortices reconnecting. Given the unique spatiotemporal evolution, we also analyzed the relativistic angular momentum of these electromagnetic fields.

physics.optics↗

arXiv2026

Knotted spacetime electromagnetic vortex unlinking and unknotting with vector and scalar reconnections and field twist compensation

Optical vortex knots have been realized in monochromatic laser beams, but monochromatic fields are stationary and their topology is frozen. Here we show that knotted spatiotemporal vortices, whose phase singularities form closed loops in spacetime, undergo topology changing reconnections with free space propagation. When null lines of different vector components unlink, the electric spin, magnetic spin, linear momentum, and electromagnetic helicity densities, each built from a specific pair of field components, twist to exactly compensate the change in linking number. This compensation is enforced by the argument principle where the total for each component pair, combining mutual phase twist, geometric linking, and open-line threading, vanishes identically and remains exactly zero through all reconnection events.

physics.optics↗

arXiv2025

Arbitrary geometry electromagnetic spatiotemporal vortices from phase velocity shearing

In fluids, vortices form at boundaries between flows of different velocities. Here, we show that pulsed electromagnetic waves form spatiotemporal vortices when light straddles media of different phase velocities. When the resulting relative time-delay is on the order of the pulse duration of light, spatiotemporal optical vortices (STOVs) are formed. This method allows generating arbitrary geometry spatiotemporal vortices, something impossible with previously demonstrated generation schemes. We provide experimental results showing THz frequency light can be encoded with arbitrary spatiotemporal vortex geometries using simple planar fused filament prints made from a commercial 3D printer. We provide several demonstrations of unique geometries including squares, triangles, ring arrays, and arbitrary curves that cannot be generated with existing techniques. We also show that multiple ring and line vortices can be formed simultaneously, which undergo complex reconnections with propagation. While demonstrated at THz frequencies, this concept is directly applicable to visible and infrared light and our theory offers a way for optimizing STOVs for the frequency range and pulse duration of a given light source. This technique provides a practical and straight-forward method to generate arbitrary electromagnetic spatiotemporal vortices and enables production of complex spatiotemporal phenomena like vortex reconnections.

physics.optics↗

arXiv2025

Three-dimensional Arbitrary Electromagnetic Fields and Temporal Propagation

We show that arbitrary 3D electromagnetic fields are transient solutions to Maxwell's equations and provide a simple equation to find how the field evolves over time. Multiple 3D fields can be realized at different times by superposing with an initial phase. Phase optimization algorithms allow for a phase-only modulated input signal. The necessary input wavepacket before a focus lens to create the 3D field can be found by finding the time-variation through a spatial plane. These results provide a way for designing arbitrary transient 3D waves and finding the wavepacket needed to input into a focusing lens.

physics.optics↗

arXiv2024

Laser Printing of Silver and Silver Oxide

We show that direct laser writing in aqueous silver nitrate with a $\lambda$ = 1030 nm femtosecond laser results in deposition of a mixture of silver oxide and silver, in contrast to the pure silver deposition previously reported with 780 nm femtosecond direct laser writing. However, adding photoinitiator prevents silver oxide formation in a concentration-dependent manner. As a result, the resistivity of the material can also be controlled by photoinitiator concentration with resistivity being reduced from approximately 9e-3 $\Omega$m to 3e-7 $\Omega$m. Silver oxide peaks dominate the X-ray diffraction spectra when no photoinitiator is present, while the peaks disappear with photoinitiator concentrations above 0.05 wt%. A THz polarizer and metamaterial are printed as a demonstration of silver oxide printing.

physics.optics↗