Hybrid Hermite-Laguerre-Gaussian vector modes.

Vector modes are well-defined field distributions with spatially varying polarization states, rendering them irreducible to the product of a single spatial mode and a single polarization state. Traditionally, the spatial degree of freedom of vector modes is constructed using two orthogonal modes from the same family. Here, we introduce a novel class of vector modes whose spatial degree of freedom is encoded by combining modes from both the Hermite- and Laguerre-Gaussian families, ensuring that the modes are shape-invariant upon propagation.

Helico-conical vector beams.

In this work, we propose and demonstrate experimentally a new family of vector beams, the helico-conical vector beams (HCVBs), whose spatial degree of freedom is encoded in the helico-conical optical beams. We use Stokes polarimetry to study their properties and find that upon propagation their transverse polarization distribution evolves from nonhomogeneous to quasihomogeneous, such that even though their global degree of nonseparability remains constant, locally it decreases to a minimum value as z → ∞. We corroborated this quantitatively using the Hellinger distance, a novel metric for vectorness that applies to spatially disjoint vector modes.