arXiv subjects

Pierre Bon

Publications and source records attributed to Pierre Bon.

5 recordsLinked to original sources

arXiv2024

Quantitative phase microscopies: accuracy comparison

This article presents a thorough comparison of themain QPM techniques, focusing on their accuracy in terms of measurement precision and trueness. We focus on 8 techniques, namely digital holographic microscopy (DHM), cross-grating wavefront microscopy (CGM), which is based on QLSI (quadriwave lateral shearing interferometry), diffraction phase microscopy (DPM), differential phase-contrast (DPC) microscopy, phase-shifting interferometry (PSI) imaging, Fourier phase microscopy (FPM), spatial light interference microscopy (SLIM), and transport-of-intensity equation (TIE) imaging. For this purpose, we used a home-made numerical toolbox based on discrete dipole approximation (IF-DDA). This toolbox is designed to compute the electromagnetic field at the sample plane of a microscope, irrespective of the object's complexity or the illumination conditions. We upgraded this toolbox to enable it to model any type of QPM, and to take into account shot noise. In a nutshell, the results show that DHM and PSI are inherently free from artefacts and rather suffer from coherent noise; In CGM, DPC, DPM and TIE, there is a trade off between precision and trueness, which can be balanced by varying one experimental parameter; FPM and SLIM suffer from inherent artefacts that cannot be discarded experimentally in most cases, making the techniques not quantitative especially for large objects covering a large part of the field of view, such as eukaryotic cells.

physics.optics↗

arXiv2023

Label-free image scanning microscopy for kHz super-resolution imaging and single particle tracking

We report the modification of a label-free image scanning microscope (ISM) to perform asynchronous 2D imaging at 24kHz while keeping the lateral resolution gain and background rejection of a regular label-free ISM setup. Our method uses a resonant mirror oscillating at 12kHz for one-direction scanning and a chromatic line for instantaneous scanning in the other direction. We adapt optical photon reassignment in this scanning regime to perform fully optical super-resolution imaging. We exploit the kHz imaging capabilities of this confocal imaging system for single nanoparticle tracking down to 20nm for gold and 50nm for silica particles as well as imaging freely moving Lactobacillus with improved resolution.

physics.optics↗

arXiv2023

Optical signal-based improvement of individual nanoparticle tracking analysis

Nanoparticle Tracking Analysis (NTA) provides a simple method to determine individual nanoparticle size. However, because size quantification is based on the slowly converging statistical law of random event, its intrinsic error is large, especially in case of limited event number, e.g. for weak scattering nanoparticles. Here, we introduce an NTA improvement by analyzing each individual NP trajectory while taking into account the other trajectories with a weighting coefficient. This weighting coefficient is directly derived from the optical signature of each particle measured by quantitative phase microscopy. The simulations and experimental results demonstrate the improvement of NTA accuracy, not only for mono-disperse but also for poly-disperse particle solutions.

eess.SP↗

arXiv2023

A Binary Annular Phase Mask to Regulate Spherical Aberration and Allow Super-Localization in Single-Particle Tracking over Extended Depth-of-Focus

Important applications of single-particle tracking (SPT) aim at deciphering the diffusion properties of single fluorescent nanoparticles immersed in heterogeneous environments, such as multi-cellular biological tissues. To maximize the particle localization precision in such complex environments, high numerical aperture objectives are often required, which intrinsically restrict depth-of-focus (DOF) to less than a micrometer and impedes recording long trajectories when particles escape the plane of focus. In this work, we show that a simple binary phase mask can work with the spherical aberration inevitably induced by thick sample inhomogeneities, to extend the DOF of a single-molecule fluorescence microscope over more than 4 {\mu}m. The effect of point-spread-function (PSF) engineering over spherical aberration regularizes inhomogeneities of the PSF along the optical axis by restricting it to a narrow distribution. This allows the use of a single fitting function (i.e. Gaussian function) to localize single emitters over the whole extended DOF. Application of this simple approach on diffusing nanoparticles demonstrate that SPT trajectories can be recorded on significantly longer times.

physics.optics↗

arXiv2023

Label-free single nanoparticle identification and characterization including infectious emergent virus

Screening of unknown particles, including viruses and nanoparticles, is key in medicine, industry and pollutant determination. However, existing techniques require sample a priori knowledge or modification (e.g. fluorescence). Here we introduce RYtov MIcroscopy for Nanoparticles Identification (RYMINI), a noninvasive and non-destructive optical approach that is combining holographic labelfree 3D tracking and high-sensitivity quantitative phase imaging into a compact optical setup. Dedicated to the characterization of nano-objects in solution, it is compatible with highly demanding environments such as level-3 biological laboratories. Metrological characterization has been performed at the level of each single object on both absorbing and transparent particles as well as on infectious HIV-1, SARS-CoV-2 and extracellular vesicles in solution. We demonstrate the capability of RYMINI to determine the nature, concentration, size, complex refractive index and mass of each single particle. We discuss the application of the method in unknown solution without requiring any knowledge or model of the particles' response. It paves the way to label-free nano-object identification in terra incognita.

physics.optics↗