arXiv subjects

Pawel Szczypkowski

Publications and source records attributed to Pawel Szczypkowski.

4 recordsLinked to original sources

arXiv2026

Non-invasive super-resolution imaging through scattering media using highly nonlinear labels

While scattered light conveys most of the information we perceive, scattering may also distort that information before it reaches our detectors. The problem is acute in many applications, such as in high-resolution microscopy of biological tissue, where scattering degrades both resolution and signal-to-noise ratio. Here, for the first time, we demonstrate that combining two intrinsic properties of scattered light: speckle statistics and the memory effect, with highly non-linear optical response yields, rather surprisingly, super-resolution, low-background, non-invasive imaging of objects completely hidden behind a strongly scattering, opaque layers. Crucially, our technique of Nonlinear Imaging with Speckle Excitation (NISE) does not resort to wavefront shaping, adaptive optics, complicated optical setups, or iterative image reconstruction algorithms. Because the strategy relies solely on the properties of scattered light and high-order nonlinear response of the luminescent labels, it can be applied to any speckle-forming propagation, from biological tissue to multicore fibers, combined with any type of phenomenon that exhibits a sufficiently high order nonlinearity.

physics.optics↗

arXiv2026

Low Photon Number Non-Invasive Imaging Through Time-Varying Diffusers

Optical imaging plays a crucial role in advancing science and technology, enabling applications in fields ranging from biomedicine to astronomy. However, imaging through scattering media such as biological tissues, fog, or turbulent atmosphere remains a major challenge. Light scattering and absorption in such media make imaging challenging; in the case of time-varying scatterers and low light regime imaging of incoherent objects has not been demonstrated so far. We present the first demonstration of such non-invasive imaging of dim objects hidden behind dynamic scattering layers, obtaining robust reconstruction even at extremely low photon counts per frame. We achieve this by developing a new data-processing approach. In our experiment, we utilize a photon number resolving camera to capture a sequence of frames, containing on average, fewer than one photon per pixel. We validate our approach in microscopy, where we reconstruct images of biological samples stained with standard fluorescent dyes. Beyond microscopy, our approach can be applied in different imaging techniques, such as endoscopy based on multicore fibers or ground-based astronomical observations.

physics.optics↗

arXiv2026

Verification of continuous variable entanglement with undetected photons

We verify transverse spatial entanglement of photon-pairs generated in spontaneous parametric down conversion using a nonlinear interferometric technique without relying on any coincidence detection. We experimentally demonstrate the violation of the Einstein-Podolsky-Rosen criterion and of the Mancini-Giovannetti-Vitali-Tombesi criterion using single photon interference of one of the photons of the pairs. We also provide a comprehensive theoretical analysis. The experimental results that we have obtained show good agreement with the theoretical values. Our method performs well under experimental losses and can be applied to highly non-degenerate sources, where there are no suitable detectors for one of the photons in the quantum state and our method could also be extended to the discrete degrees of freedom to certify high-dimensional (OAM) entanglement.

quant-ph↗

arXiv2024

3D Super-resolution Optical Fluctuation Imaging with Temporal Focusing two-photon excitation

3D super-resolution fluorescence microscopy typically requires sophisticated setups, sample preparation, or long measurements. A notable exception, SOFI, only requires recording a sequence of frames and no hardware modifications whatsoever but being a wide-field method, it faces problems in thick, dense samples. We combine SOFI with temporal focusing two-photon excitation -- the wide-field method that is capable of excitation of a thin slice in 3D volume. Both methods are easy to implement in a standard microscope, and by merging them, we obtain super-resolved 3D images of neurons stained with quantum dots. Our approach offers reduced bleaching and an improved signal-to-background ratio that can be used when robust resolution improvement is required in thick, dense samples.

physics.optics↗