Two-photon-nanoprinted Pancharatnam–Berry phase element for compact high-aspect-ratio optical needle generation
Year: 2026
Type: article
Abstract: Optical needle beams combine tight transverse confinement with an extended focus length, but conventional generation methods generally require multiple diffractive and refractive components, limiting system miniaturization and integration. Here, we demonstrate a single nanoprinted Pancharatnam–Berry geometric-phase element that simultaneously performs focusing and axial beam shaping without an additional focusing lens. A multi-plane inverse-design algorithm based on Rayleigh–Sommerfeld diffraction is used to optimize the optical intensity distribution throughout the target three-dimensional volume. The resulting phase profile is encoded into the spatial orientations of anisotropic dielectric elements and fabricated by free-form two-photon nanolithography. With a diameter of approximately 100 µm, the fabricated element generates an optical needle with a transverse full width at half maximum of approximately 1.47 µm over an axial distance of 31.25 µm, corresponding to an aspect ratio exceeding 21:1. This single-element approach provides a flexible route toward compact three-dimensional light-field engineering and could facilitate miniaturized systems for optical imaging, manipulation, and laser processing.
Source: Optics Express
DOI: 10.1364/oe.616307
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,270
OpenAlex ID: W7223552728