Conference Agenda

We demonstrate centimeter-scale dual-wavelength digital holography with expanding wavefront illumination that overcomes pixel-size resolution limitations thereby achieving a diffraction-limited spatial resolution of 3.91 micrometer compared to pixel-size limited resolution of 6.9 micrometer. The proposed holographic scheme provides an efficient, high-speed, high-resolution 3D optical inspection tool for industrial metrology.

This work presents a data-driven approach for reconstructing the longitudinal

component of tightly focused optical fields using only experimentally

accessible polarimetric intensity images. A custom-designed deep neural network

is trained on simulated polarimetric mappings generated from aberrated

wavefronts through a high-NA objective. The model successfully reconstructs

the complex amplitude of the longitudinal field with high fidelity, offering a

practical and instant method for indirect measurement of longitudinal components

in tightly focused beams.

A valuable method in biological imaging is Oblique Plane Microscopy (OPM), in which a single objective lens is used to launch a tilted (oblique) light sheet into the sample and to capture the fluorescence emission light. The captured light can be focused remotely onto a glass-immersion objective, tilted to match the oblique light sheet. Combined with this bespoke objective, OPM enables the use of a high-NA, short working distance objective with high magnification, maximising resolution and fluorescence capture efficiency.

Accurate modelling of the OPM’s 3D Point Spread Function (PSF) is needed for performance and resolution analysis, image deconvolution, and combinations of OPM with Structured Illumination Microscopy (SIM). The high NA necessitates taking into account all effects of polarisation and all directions of propagation, the remote focusing construction, and the non-orthogonal optical axes of the different lenses. We have developed a fully exact vectorial model of the 3D PSF for OPM. Key elements are the vignetting and deformation of the different non-overlapping pupil planes in the optical train, and correct handling of the remote focusing. It appears that a modification of standard Fourier optics methods using non-Cartesian coordinate frames provides an efficient route to compute the 3D PSF.

Icosahedral colloidal supraparticles are of interest because of their strong spherical symmetry. A polarization-complete tomographic imaging technique is developed to study the scattering properties of icosahedral supraparticles. The results reveal that our particles exhibit angle-dependent scattering behavior and inner structures.

In this talk, we discuss the effect of plasmonic resonances on the Fisher information in the far field. We consider a metallic nanowire embedded in a silicon substrate, illuminated by a dark-field focused spot, and we investigate how its position can be estimated from the scattered far-field intensities. The Fisher information is computed for both lateral and longitudinal displacements of the nanowire, and the dependence on the illumination frequency is analyzed. We compute the complex resonance frequencies of the nanowires and show that frequencies near the real part of the plasmonic resonance frequency enhance the Fisher information. However, at the resonance frequency itself, the Fisher information drops sharply, leading to an Information Dark State in which the position of the nanowire becomes nearly undetectable. This effect is analyzed and illustrated for both gold and silver nanowires.