arXiv subjects

Subhrokoli Ghosh

Publications and source records attributed to Subhrokoli Ghosh.

3 recordsLinked to original sources

arXiv2025

Laser Guided Microbubble Lithography for Multilayer Biophotonic Heterostructures

The fabrication of multilayered heterostructures is essential for advancing microelectronic and biosensing technologies. Conventional top-down manufacturing techniques are often cost-prohibitive and unsuitable for biomedical applications. Here, we present a bottom-up fabrication method, termed microbubble lithography, which enables the in situ construction of multilayered microstructures through layer-by-layer self-assembly. This technique allows diverse materials to be integrated into coherent heterostructures. We demonstrate the platform's utility by successfully patterning a biomarker and a reporter protein, highlighting its potential for cost-effective and environmentally sustainable sensing applications.

physics.chem-ph↗

arXiv2021

Quantitative analysis of non-equilibrium systems from short-time experimental data

We provide a minimal strategy for the quantitative analysis of a large class of non-equilibrium systems in a {statistically} steady state using the short-time Thermodynamic Uncertainty Relation (TUR). From short-time trajectory data obtained from experiments, we demonstrate how we can simultaneously infer quantitatively, both the thermodynamic force field acting on the system, as well as the (potentially exact) rate of entropy production. We benchmark this scheme first for an experimental study of a colloidal particle system where exact analytical results are known, before applying it to the case of a colloidal particle in a hydrodynamical flow field, where neither analytical nor numerical results are available. In this latter case, we build an effective model of the system based on our results. In both cases, we also demonstrate that our results match with those obtained from another recently introduced scheme [Phys. Rev. X 10, 021009].

cond-mat.soft↗

arXiv2019

Self-assembly and complex manipulation of colloidal mesoscopic particles by active thermocapillary stress

We demonstrate that the active thermocapillary stresses induced by multiple microbubbles offer simple routes to directed self-assembly and complex but controllable micromanipulation of mesoscopic colloidal particles embedded in a liquid. The microbubbles are nucleated on a liquid-glass interface using optical tweezers. The flow around a single bubble causes self-assembly of the particles in rings at the bubble-base, while an asymmetric temperature profile generated across the bubble interface breaks the azimuthal symmetry of the flow, and induces simultaneous accumulation and repulsion of particles at different axial planes with respect to the bubble. The flows due to two adjacent bubbles lead to more diverse effects including the sorting of particles, and to local vorticity that causes radial and axial rotation of the particles - the latter being obtained for the first time using optical tweezers. The sorting is enabled by nucleating the bubbles on spatially discrete temperature profiles, while the vorticity is generated by nucleating them in the presence of a temperature gradient which once again causes a strong symmetry-breaking in the azimuthal flow. The flow profiles obtained in the experiments are explained by analytical solutions or qualitative explanations of the associated thermocapillary problem employing the Stokes and heat equations.

physics.flu-dyn↗