The paper's goal is to inform outreach coordinators and scientists of strategies used to develop a Light
Emitting Diode (LED) curriculum module for high school students. Field-testing the weeklong LED
curriculum, teachers acquired new instructional strategies to develop students career and global workforce
skills in STEM disciplines. The National Science Foundation (NSF) Innovative Technology Experiences
for Students and Teachers (ITEST) funded program session will highlight initial findings of the
developmental process, review data of the pilot study with middle and high school teachers participating in
a teacher workshop and student program offered by The Science House of North Carolina State University.
Optical manipulation of nano- and micro-scale particles via optical tweezers and optical landscapes continues
to be of great interest in several fields, reflected by the myriad experimental pursuits suggesting selective and
parallel control over particles of anisotropic shape (blood cells, nanorods, etc.). Our work here approaches the
goal of a complete model of these phenomena by means of optical scattering principles and, specifically, the T-matrix
method. Here we describe the salient features of our model, which tends toward a complete and consistent
modeling scheme for determining the behavior of dielectric, polarizable, mesoscale particles of anisotropic shape
in arbitrary intensity gradients. We explore forces and torques caused by periodic optical landscapes as well as
torques induced by the polarization orientation of the electric field.
Optical trapping, mixing, and sorting of micro- and nano-scale particles of arbitrary shape (e.g., blood cells
and nanorods) are but a few of the burgeoning applications of optical interference landscapes. Due to their
non-invasive, non-contact manipulation potential, biologists and nanotechnologists alike are showing increased
interest in this area and experimental results continue to be promising. A complete and reliable theoretical
description of the particles' response within these fields will allow us to accurately predict their behavior and
motion. We develop an electrostatic model of the optical force and torque on anisotropic particles in optical
intensity gradients. The complete optical field is defined and a Maxwell stress tensor approach is taken to realize
the force and torque induced by the electric field due to the polarizability of the particle. We utilize the properties
of real dielectrics and steady state optical fields to extend this approach to the electrodynamic case inherent in
optical trapping. We then compare our results against our recently reported form factor approach and use the
differences to try to determine the importance of polarizability in optical trapping.
We have developed an order of magnitude model for the the complete motion - translation and rotation - of spheroidal microparticles under the influence of intense optical landscapes and laminar flow using force and torque balances within the system. Our fields of interest are periodic interference profiles, sometimes termed optical landscapes, that can be formed by simple holography. When given an arbitrary landscape, our model predicts that, in general, spheroidal particles become trapped at a lower potential threshold than do spherical particles of an equivalent volume. In addition, we show that optical landscapes exhibit exponential trapping selectivity based on particle size and shape, effectively adding a further dimension of control over which to trap, influence, and sort particles within the same flow.
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