Aristide Dogariu

Abstract: Methods and systems for using dynamic light scattering, for investigating local rheological responses of complex fluids over a frequency range larger than that provided by standard instrumentation. A low-coherence radiation source is used with fiber optics to allow measurements of small volume spacing of up to approximately 1/10 of a picoliter. The methods and systems are based on dynamic light scattering, for investigating the local rheological response of a complex fluid over a frequency range larger than that provided by standard mechanical instrumentation. The low-coherence radiation used in a fiber optics configuration allows the measurements to be confined to a small volume around a tenth of a picoliter. The ability of the method to accurately measure both loss and storage moduli has been tested using both simple Newtonian liquids and viscoelastic, complex fluids. Monitoring liquid-gel transitions in polymer solutions has also been demonstrated. The unique capability of the technique to localize the measurement volume can be used for three-dimensional mapping of rheological properties in heterogeneous systems. Other embodiments can use open-air setups instead of optical fibers to transmit and receive the low coherence light.

TL;DR: This work presents a general procedure to directly measure the field transfer matrix of a linear medium without regard to the scattering regime and demonstrates the ability of this procedure to correctly measure field transfer matrices and use them to recover the polarization state of incident illumination.

TL;DR: It is shown that a discrete random-walk model can be used to determine the magnitude of the dielectric constant fluctuations at subwavelength scales which, in turn, describes the morphology of optically inhomogeneous media.

TL;DR: It is shown that, despite a significant scattering originating in the bulk of such diffusive media, the nontrivial behavior of the off-diagonal Muller matrix is primarily due to surface scattering phenomena.

TL;DR: It is shown that a thermally induced in-fiber fluid instability permits the “digital design” of multimaterial photonic particles: the precise allocation of high refractive-index contrast materials at independently addressable radial and azimuthal coordinates within its 3D architecture.