Research Projects in the Laboratory for Mesoscopics and
Quantum Microscopies
The ability to manipulate micro- and nano-scale structures is clearly at the forefront of current scientific concerns -- and is also an area which is currently seeing very rapid progress. At Illinois Wesleyan, we are interested in optical momentum, optical forces, and optical torques and -- generically -- in micro- and nano-scale transport and assembly processes, as well as medium-mediated interactions.
Techniques using lasers to trap and manipulate matter have already aided our understanding of (nano-scale) molecular motors and unraveling DNA, and have also had great impact on studies of (micro-scale) cellular-level physics and hydrodynamic interactions. Yet, while basic optical traps have been around for some time, a "next generation" of techniques is promising to revolutionize the degree of control possible for localizing, guiding, spinning, and even optically organizing matter on length scales that are of enormous technological importance.
Current work significantly extends the capabilities of laser tweezing, making it possible to sculpt light into modes and patterns that provide important new functionality. For example, we can now controllably adjust the orientation of trapped matter - a core capability for the sort of "lock and key" assembly required by some biological (and micro-machine) systems.
We also use novel light modes and patterns to create optical "bottles" for cold atoms, laser "guiding" of matter, reconfigurable optical "sieves" for separation of bio-molecules, along with one-, two-, and three-dimensional optical "lattices" which allow for a variety of basic studies. To do all of this, we pass laser beams through computer-generated holograms (of our own design), thereby forming a tailored potential energy landscape which causes micro- or nanoparticles to assemble themselves into a desired structure. Thus, in the end, we produce holograms that are not merely ethereal images; they have corporeal substance.
Our work also aims to enhance the extent of nanoparticle localization (i.e., reducing trap volumes) and of control over large-scale organization of micro- and nanocomponents. On the nano-scale, we envision a variety of single-molecule studies, as well as highly selective size- and shape-dependent optical sorting of chemical nanoprobes. On the microscale, interest in organizing components into larger structures or assemblies stems from many quarters, including the desire to organize biological cells during organ and tissue growth, the desire to create photonic bandgap materials and devices, and the desire to create model thermodynamic systems for the study and elucidation of collective phenomena/many-body effects in tailored potential landscapes and even of biological assembly processes. It should also be noted that the microfluidic technologies which currently hold so much promise for lab-on-a-chip technologies require novel approaches to mixing and sorting, and the reconfigurability of optical micromanipulation has much to offer.
List of
Publications Lab Photos
User-Friendly, Freeware Particle Tracking Software
Don't miss OTOM '08: Optical Trapping & Optical Micromanipulation
Conference
San Diego, CA
Aug 10 - Aug 14, 2008
(Proceedings from previous years of the conference contain large collections of relevant papers:
OTOM '07
,
OTOM '06
,
OTOM '05
,
and the
OTOM '04
.)