Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · 2611.03275

Geometric Phase and Spinor Beam Dynamics of Paraxial Beams

Jonathan M. Nichols·Christopher Griffin·Steven N. Rodriguez·Daniel V. Nickel·Frank Bucholtz
View original source ↗Read source document ↗Export metadata ↓

Abstract

We show that treating a paraxially propagating electric field as a spinor provides a natural way to include geometric phase in beam propagation models. Importantly, by exploiting differences in the way geometric phase and dynamical phase accrue during propagation, we show that spatial variations in the former can have surprising and rather remarkable consequences for beam dynamics. As an example, we design a beam with a centroid that is predicted to follow a curved path through free space, a prediction we subsequently validate in experiment. The model presented herein does not contradict existing propagation models, but rather shows how to leverage the extra degree of freedom afforded by the spinor angle to make new predictions.

Explore related subjects

physics.opticsmath-phmath.MP

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Jonathan M. Nichols, Christopher Griffin, Steven N. Rodriguez, Daniel V. Nickel, Frank Bucholtz. 2026-11-02. Geometric Phase and Spinor Beam Dynamics of Paraxial Beams. https://arxiv.org/abs/2611.03275

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Valley polarization driven by two-color circular fields from a strong-field tunneling perspective

Valley polarization in hexagonal materials driven by the form of the lightwave and its orientation relative to the lattice, rather than solely by the helicity of the driver, has recently been demonstrated both theoretically and experimentally. This has extended valley control to the non-resonant, sub-cycle regime and to inversion-symmetric materials. One interpretation of this field-orientation-dependent valley polarization is that the laser-dressed, cycle-averaged band structure obtained from a Floquet-type approach is modified so as to lift the degeneracy between the valleys. Here, we derive a complementary explanation based on strong-field tunneling dynamics. We show that the effective valley gap at the dominant injection times depends on the orientation of the field relative to the lattice through the trigonal-warping term of the low-energy dispersion. We derive general expressions for co- and counter-rotating $ω+Nω$ fields and show that the leading orientation-dependent contribution survives the cycle average only for field configurations compatible with the threefold lattice symmetry, most notably counter-rotating $ω+2ω$ and co-rotating $ω+4ω$ fields.

physics.optics↗
arXiv2026

Advances in the Vacuum Magnetic Birefringence measurement using a pulsed Foil Coil

In this paper, in the framework of the {\it Biréfringence Magnétique du Vide} (BMV) experiment, we present our current apparatus in detail and we discuss its critical points. We also report the results obtained using specially designed pulsed coils called Foil Coils. Our novel measurement of the vacuum linear magnetic birefringence constant is $K_{VMB} < 1.7 \cdot 10^{-21}~\text{T}^{-2}$ at a confidence level of 68$\%$, which is an improvement with respect to our previous 2014 measurement.

physics.optics↗
arXiv2026

Asymptotic electromagnetic transition conditions for thin layers: the arithmetic-mean field and susceptibility hybridization

Effective transition conditions that replace a thin polarizable layer by a zero-thickness sheet are commonly applied in electromagnetic models of two-dimensional (2D) materials and metasurfaces. These conditions usually take the arithmetic mean of the fields on either side as the polarizing field at the boundary, and characterize the layer by the $0^\mathrm{th}$ moment of its susceptibility, but both choices are typically imposed rather than derived. We derive transition conditions for a finite-thickness, in-plane homogeneous, in-plane isotropic layer with a general nonlocal susceptibility, using a single-scale asymptotic expansion in $η= l\max(k_0,q)$, where $l$ is the layer thickness, $k_0$ the free-space wavenumber and $q$ the in-plane wavenumber. The sheet limit must be taken after resumming the out-of-plane depolarizing field, as this ensures that the resulting sheet susceptibility is independent of the material thickness. The arithmetic mean then emerges as the leading-order polarizing field for general susceptibility profiles. Asymmetries in the layer profile modify the effective susceptibility appearing in the transition conditions, rather than altering the arithmetic-mean field prescription. If the spatial profile is not even in both out-of-plane coordinates, in-plane and out-of-plane response hybridize, turning the diagonal volumetric susceptibility into a $q$-dependent effective tensor surface susceptibility with off-diagonal components. Mirror symmetry alone does not remove this hybridization. Comparison with exact solutions for local and separable layers shows that the derived conditions remain accurate to $O(η)$ across propagating and evanescent excitations, whereas the standard sheet conditions fail once hybridization becomes appreciable.

physics.optics↗