arXiv subjects

Fabio Borbone

Publications and source records attributed to Fabio Borbone.

5 recordsLinked to original sources

arXiv2025

All-optical Lithography for Spatiotemporal Patterning of High-Modulation Azopolymer Microreliefs

Microstructured surfaces are central to photonics, biointerfaces, and coating technologies, but they are typically fabricated through multistep workflows involving masks, molds, and postprocessing. Azopolymers offer a direct light-driven route to surface structuring, yet holographic photopatterning of flat films has mainly remain limited to smooth, shallow, and engraving-like reliefs with limited vertical modulation. Here we show that computer-generated holograms with co-designed bright and dark regions can spatially confine inward mass transport and directly generate isolated protruding microstructures with several micrometer surface modulation from pristine flat azopolymer films. Single exposures produce individual protrusions and protrusion arrays, whereas sequential tailored exposures further reshape microrelief morphology over time. Using this spatiotemporal scheme, we fabricate flattenedtop micropillars, programmable arrays, freeform continuous microreliefs, and hierarchical structures from a pristine flat film, and we demonstrate write-erase-rewrite cycles in the same surface region. These results establish an all-optical strategy for generating and reconfiguring high modulation azopolymer microreliefs through combined control of spatial and temporal degrees of freedom of holographic illumination.

physics.optics↗

arXiv2025

Stress-driven photo-reconfiguration of surface microstructures via vectorial field-guided lithography

Pattern formation driven by mechanical stress plays a fundamental role in shaping structural organization in both natural and human-made systems. Using light as a vectorial stimulus may offer a powerful route to control stress-induced pattern formation in materials. However, achieving localized, programmable, and predictable control of individual microstructures via structured polarization fields has remained a major challenge. Here, we introduce vectorial field-guided lithography, a novel approach that leverages fully structured polarization fields as lithographic tools to enable the stress-driven reconfiguration of pre-patterned azopolymer microstructures with an unprecedented degree of flexibility, complexity, and diversity. By building on the Viscoplastic PhotoAlignment model, which describes the azopolymer deformation as stress response to structured light, we quantitatively demonstrate and predict complex surface architectures generated by programmable light-induced stress pathways using a digital polarization rotator implemented via a spatial light modulator. We model and experimentally achieve single-step formation of anisotropic, bent, and chiral microstructures from a single pre-patterned geometry. Our results reveal an exceptional control over local microstructure morphology and establish, for the first time, a comprehensive theoretical framework capable of quantitatively designing and fabricating target morphologies on azopolymers. This work moves beyond conventional intensity-based photopatterning and demonstrates that the full vectorial nature of light can dictate the mechanical reshaping of functional polymer surfaces, providing a new platform for the programmable design of complex micro-architectures with applications in photonics, microfluidics, and biology.

physics.optics↗

arXiv2023

Super-resolution imaging for the detection of low-energy ion tracks in fine-grained nuclear emulsions

We propose a new wide-field imaging method that exploits the Localized Surface Plasmon Resonance phenomenon to produce super-resolution images with an optical microscope equipped with a custom design polarization analyzer module. In this paper we describe the method and apply it to the analysis of low-energy carbon ion tracks implanted in a nuclear emulsion film. The result is then compared with the measurements of the same tracks carried out at an electronic microscope. The images set side by side show their close similarity. The resolution achieved with the current microscope setup is estimated to be about 50 nm.

astro-ph.IM↗

arXiv2022

Reprogrammable holograms from maskless surface photo-morphing

Holographic technologies have the potentiality to impact our everyday life in many sectors including science, education, entertainment, art, and healthcare. Although holographic screens and projectors are part of common imagination since long time, they are still at initial stages of development and integration. Recent achievements of metasurface and flat optics research gave an unprecedented strength to this field, overcoming critical aspects as efficiency, size and flexibility of conventional optics and liquid crystal technologies. However, although diffractive and metasurface holographic projectors with advanced functionalities and improved efficiencies are continuously reported, they are static devices, requiring demanding, burdensome, and irreversible manufacturing processes. Here we report an all-optical and single-step lithographic framework for the fabrication of diffractive holographic projectors directly on the surface of a photo-morphable polymer film. Real-time optimization during the accurate surface patterning and fully structural reconfigurability allowed for the first prototype of a fully reprogrammable pixel-less morphological projector, opening new routes for holographic image displaying and optical data sharing.

physics.optics↗

arXiv2012

Light-induced spiral mass transport in azo-polymer films under vortex-beam illumination

When an azobenzene-containing polymer film is exposed to a non-uniform illumination, a light-induced mass migration process may be induced, leading to the formation of relief patterns on the polymer free surface. Despite a research effort of many years and several proposed models many aspects of this phenomenon remain not well understood. Here we report the appearance of spiral-shaped relief patterns on the polymer under the illumination of focused Laguerre-Gauss beams, having helical wavefront and an optical vortex at their axis. The induced spiral reliefs are sensitive to the vortex topological charge and to the wavefront handedness. These findings are unexpected, because the "doughnut"-shaped intensity profile of Laguerre- Gauss beams contains no information about the wavefront handedness. We propose a model that explains the main features of this phenomenon from the surface-mediated interference of the longitudinal and the transverse components of the optical field. These results may find applications in optical micro- and nanolithography and optical-field.

physics.optics↗