Research Interests

 

My research interests are varied and include optical light scattering, biophysics, and most recently sonoluminescence.

 

 

 

Optical Light Scattering

The optical light scattering experiments that we have conducted include coherent backscattering of light, time-resolved photon correlation spectroscopy, imaging absorbing structures within a random media, and speckle statistics.

 

Coherent backscattering of light is a phenomenon in which photons traveling time-reversed paths self-interfere in the backscattered direction leading to the observance of an enhanced intensity cone.  This is an indication of so-called weak localization of photons and is also observed in other systems in which waves are propagating through highly scattering media.

 

 

Time-resolved photon correlation spectroscopy is a technique in which the motion of particles suspended in a fluid causes the light scattered by these particles to fluctuate in time.  By analyzing these intensity fluctuations the particle size may be determined.  Adding time-resolved detection enables denser samples to be probed.

 

 

Optical coherence tomography uses low-coherence light to image absorbing structures embedded within a highly scattering medium.  The optical schematic, depicted above, represents the experimental arrangement we used to investigate the dependence of the ability to image on photon transport and extinction mean-free-path lengths.

 

 

A speckle statistics study consists of determining the intensity distribution associated with the light in each speckle coherence area as the incident polarization is varied.  Photon behavior may then be inferred.

 

 

 

Biophysics

Our biophysics research program centers on the study of the structural characteristics of swarms in nature.  The characteristics of such aggregations, as a whole, may be used to infer the behavioral attributes of the individuals comprising the swarms by using radial distribution and pair-correlation functions.  We have applied these techniques to various zooplankton swarms.  The image above shows ostracod aggregations at two different densities.  This work has a dedicated web page that may be found by clicking on this link OR you may read our recent paper by clicking on this link.

 

 

 

Sonoluminescence

Sonoluminescence is the emission of ultra-short bursts of light from imploding bubbles trapped in a liquid when driven at resonance by a sound field of sufficient intensity.  We use a single acoustical horn driving a rectangular chamber at resonance to produce single bubble sonoluminescence.  We are investigating how various additives affect the sonoluminescent spectrum.