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Optical Focusing beyond the Diffraction Limit via Vortex-Assisted Transient Microlenses
journal contribution
posted on 2020-03-26, 20:29 authored by Eitan Edrei, Giuliano ScarcelliFocusing
light beyond the diffraction limit is among the greatest
challenges in optical sciences, which would revolutionize many optical
technologies from imaging and optical trapping to light delivery and
photomedicine. To achieve subdiffraction focusing, metamaterials,
materials with engineered scattering properties, or attached microspheres
have been proposed. Here we introduce a new paradigm to achieve a
physical focus beyond the diffraction limit without additional optical
elements or exogenous labels, but only using light–matter interactions.
We spatially control light absorption within the focal region of a
lens to generate a transient heat source and sculpt a semiparabolic
refractive index pattern within the sample itself. This effectively
generates a converging microlens with a focusing spot below the diffraction
limit of the optical system that can be used for super-resolution
imaging by scanning the spot across the sample. Our method is broadly
compatible with imaging and focusing systems used in many applications.