arXiv subjects

Yu-Xuan Ren

Publications and source records attributed to Yu-Xuan Ren.

6 recordsLinked to original sources

arXiv2026

Optical Self-Trapping and Nonlinear Light-Matter Interactions in Biological Soft Matter

Low-scattering, deep-penetration light transport in biological media remains a pivotal challenge for biophotonic technologies, including biomedical imaging, optical diagnostics, and photodynamic therapy. This review builds upon and extends our earlier studies of nonlinear optical self-trapping and optically induced waveguiding in biological suspensions, such as human erythrocytes and cyanobacteria, where light-matter coupling is governed by optical-force-mediated particle redistribution. Recent progress has revealed increasingly rich and complex regimes, including the propagation and nonlinear self-action of structured (vortex) beams in biological environments, as well as nonlinear responses dominated by thermally driven mechanisms in absorptive biomolecular solutions (e.g., heme and chlorophyll). We place particular emphasis on distinctive nonlinear phenomena observed in these systems, including spatial self-phase modulation, optical-force-induced sculpturing of effective energy landscapes, and quasi-waveguide formation in soft, heterogeneous biological media. We conclude by highlighting emerging opportunities to harness these nonlinear behaviors for deep-tissue imaging, label-free biosensing, and the realization of biocompatible photonic structures and devices assembled directly from living or hybrid biological matter.

physics.optics↗

arXiv2026

Controllable Lateral Optical Forces on Janus Particles in Fluid Media

Optical forces - studied since the earliest days of laser physics - continue to reveal rich dynamics and enable powerful tools for manipulation of objects on micro- and nanoscales, and even individual atoms. Lateral optical forces, which act perpendicular to the direction of beam propagation, are particularly intriguing but have largely been restricted to interface geometries such as air - water boundaries. Here, we realize tunable lateral optical force entirely within a fluid environment by using Janus particles: dielectric microspheres half-coated with gold. We show that the lateral optical force arises from scattering asymmetry induced by the asymmetric structure of the particles; it can be tuned by adjusting the polarization angle of a linearly polarized beam, but also particle parameters including their size and orientation. Experimentally, we directly observe fully reversible lateral propulsion of Janus particles in water merely by rotating the polarization direction, in excellent agreement with theoretical predictions. These results establish a new mechanism for programmable, polarization-controlled optical manipulation, with promising implications for biophotonics, microfluidics, and active soft-matter systems.

physics.optics↗

arXiv2024

A Physics-Inspired Deep Learning Framework with Polar Coordinate Attention for Ptychographic Imaging

Ptychographic imaging confronts inherent challenges in applying deep learning for phase retrieval from diffraction patterns. Conventional neural architectures, both convolutional neural networks and Transformer-based methods, are optimized for natural images with Euclidean spatial neighborhood-based inductive biases that exhibit geometric mismatch with the concentric coherent patterns characteristic of diffraction data in reciprocal space. In this paper, we present PPN, a physics-inspired deep learning network with Polar Coordinate Attention (PoCA) for ptychographic imaging, that aligns neural inductive biases with diffraction physics through a dual-branch architecture separating local feature extraction from non-local coherence modeling. It consists of a PoCA mechanism that replaces Euclidean spatial priors with physically consistent radial-angular correlations. PPN outperforms existing end-to-end models, with spectral and spatial analysis confirming its greater preservation of high-frequency details. Notably, PPN maintains robust performance compared to iterative methods even at low overlap ratios, making it well suited for high-throughput imaging in real-world acquisition scenarios for samples with consistent structural characteristics.

physics.optics↗

arXiv2021

Optical trapping with structured light

Optical trapping describes the interaction between light and matter to manipulate micro-objects through momentum transfer. In the case of 3D trapping with a single beam, this is termed optical tweezers. Optical tweezers are a powerful and non-invasive tool for manipulating small objects, which have become indispensable in many fields, including physics, biology, soft condensed matter, amongst others. In the early days, optical trapping were typically used with a single Gaussian beam. In recent years, we have witnessed the rapid progress in the use of structured light beams with customized phase, amplitude and polarization in optical trapping. Unusual beam properties, such as phase singularities on-axis, propagation invariant nature, have opened up novel capabilities to the study of micromanipulation in liquid, air and vacuum. In this review, we summarize the recent advances in the field of optical trapping using structured light beams.

physics.optics↗

arXiv2019

Behavioral similarity of dissipative solitons in an ultrafast fiber laser

Dissipative solitons are non-dispersive localized waves that exhibit intriguing dynamics. In optical systems, the discovery of new soliton dynamics and how to accurately manipulate dissipative solitons are still largely unexplored and challenging in the ultrafast fiber laser community. Herein, we unveil a new type of dissipative soliton behavior in a net-normal-dispersion bidirectional ultrafast fiber laser. That is, the bidirectional dissipative solitons will always reveal similar spectral and temporal characteristics through common gain and loss modulation, even if the transient instability is involved. The behavioral similarity enables us to accurately design the soliton patterns by introducing seed pulses through loss modulation. As a proof-of-concept application, the precise and flexible manipulation of multi-soliton patterns is demonstrated. These findings will shed new insights into the complex dissipative soliton dynamics, and also beneficial for designing ultrafast lasers with desirable soliton patterns for practical applications.

physics.optics↗

arXiv2015

Shaping symmetric Airy beam through binary amplitude modulation for ultralong needle focus

Needle-like electromagnetic fields has various advantages for the applications in high-resolution imaging, Raman Spectroscopy, as well as long-distance optical transportation. The realization of such field often requires high numerical aperture (NA) objective lens and the transmission masks. We demonstrate an ultralong needle-like focus in the optical range produced with an ordinary lens. This is achieved by focusing a symmetric Airy beam (SAB) generated via binary spectral modulation with a digital micromirror device(DMD). Such amplitude modulation technique is able to shape traditional Airy beams, SABs, as well as the dynamic transition modes between the one-dimensional(1D) and two-dimensional (2D) symmetric Airy modes. The created 2D SAB was characterized through measurement of the propagating fields with one of the four main lobes blocked by an opaque mask. The 2D SAB was verified to exhibit self-healing property against propagation with the obstructed major lobe reconstructed after a certain distance. We further produced an elongated focal line by concentrating the SAB via lenses with different NA's, and achieved an ultralong longitudinal needle focus. The produced long needle focus will be applied in optical, chemical, and biological sciences.

physics.optics↗