Dielectric‐Confinement‐Induced in‐Plane Photoelectric Anisotropy in Isotropic Quasi‐1D γ‐GaS Nanoribbon

The growing demand for polarized photodetection has driven the need for compact, integrated, and multifunctional device architectures. Although one-dimensional (1D) materials are of significant interest for their innate polarization sensitivity among viable integration strategies, current research has largely overlooked the anisotropy induced by geometric dielectric confinement, remaining mainly focused on optoelectronic anisotropy from lattice symmetry breaking. To bridge the gap, here we investigate geometry-governed optoelectronic anisotropy in quasi-1D GaS nanoribbons with intrinsically isotropic atomic structures. Dielectric mismatch between the ribbon and its surroundings leads to a general polarization-dependent photoresponse during near-field scattering. Steady-state and transient spectroscopy further reveal that the dielectric confinement substantially modulates light absorption, phonon scattering, and carrier diffusion. Remarkably, this geometry-governed anisotropy exhibits sufficient strength and robustness to effectively support applications in areas such as polarized imaging, stress mapping, and visual cryptography. Our work provides fundamental insights into the optoelectronic anisotropy of 1D nanomaterials and offers a rational basis for exciting material properties and optimizing device designs in future polarized photonics.