arXiv subjects

Shireen Goh

Publications and source records attributed to Shireen Goh.

2 recordsLinked to original sources

arXiv2024

Dense Suspension Inertial Microfluidic Particle Theory (DENSE-IMPACT) Model for Elucidating Outer Wall Focusing at High Cell Densities

Inertial microfluidics has been limited to dilute particle concentrations due to defocusing (spreading out) at high particle concentrations. We observe a counterintuitive shift of focusing to the outer curved wall under high concentration flow, which contradicts the existing particle focusing theory. We developed a multiphase model incorporating lift forces and particle-particle interactions to explain this behaviour. Numerical simulations validated by experimental data reveal the shift is governed by the ratio of the lift force strength to that of particle interaction frequencies.

physics.flu-dyn↗

arXiv2006

Low-Light-Level Optical Interactions with Rubidium Vapor in a Photonic Bandgap Fiber

We show that a Rubidium vapor can be produced within the core of a photonic band-gap fiber yielding an optical depth in excess of 2000. Our technique for producing the vapor is based on coating the inner walls of the fiber core with an organosilane and using light-induced atomic desorption to release Rb atoms into the core. We develop a model to describe the dynamics of the atomic density, and as an initial demonstration of the potential of this system for supporting ultra-low-level nonlinear optical interactions, we perform electromagnetically-induced transparency with control-field powers in the nanowatt regime, which represents more than a 1000-fold reduction from the power required for bulk, focused geometries.

physics.optics↗