Research

Optics and Photonics
Photonic band structure refers to the modification of the propagation properties of electromagnetic waves traveling through a periodically modulated dielectric. As an example consider light traveling through a regularly spaced array of spherical glass beads. The effects of scattering and interference of the light by the glass beads clearly would result in a change in the propagation of the waves. The alteration in the propagation properties is particularly significant when the wavelength of the light is approximately equal to the spacing between the beads. In this regime photonic band gaps--frequency intervals in which no photon modes are allowed--can be created for appropriately designed dielectric arrays. The ability to create volumes of space in which no photons of a given band of energies can exist has a number of fundamental and applied consequences.

Slow and Fast Wave Phenomena
A fundamental concern of physics centers on understanding how waves propagate through materials. Over the past few years there has been growing interest in manipulating the speed at which waves propagate. The speed of light in vacuum, c , has typically been thought of as an upper bound that cannot be exceeded. However, in the field of optics, many researchers have created materials that permit light pulses to travel much faster than c . Similarly, systems have been created that can slow and even stop light. These exotic effects do not violate the theory of relativity nor do they upset the sequence of cause and effect. At MTSU we have specialized in wave propagation phenomena using electrical and acoustic waves instead of light. We have produced numerous research articles on fast and slow sound, including the first experimental evidence of superluminal sound (sound that travels faster than c). Similarly, we have research publications on fast and slow wave experiments with electrical signals traveling through electrical or coaxial-cable filters-including tunneling a Jimi Hendrix guitar solo faster than light!

Ellipsometric Laser Tweezers
L aser tweezers can conveniently grab and move particles whose dimensions range from tens of nanometers to tens of microns. This novel optical-tweezer nano-manipulation capability, combined with high-resolution imaging and digital image analysis, has created a new and powerful class of experimental techniques for probing the structure, mechanical deformation properties, and interactions of biological systems at cellular and molecular levels.

Astronomy Research - Planetary Radio Astronomy and Education
The analysis of radio waves from Jupiter can lead to the understanding of the nature of Jupiter's magnetosphere, plasma environment, solar-planetary connections, planet-satellite interactions, and even Jupiter's interior structure. Using both ground-based and spacecraft data, the electric and magnetic characteristics of both particles and waves are investigated. Ground based data come from the University of Florida radio telescope, and spacecraft data are available from NASA's Voyager, Galileo, and Cassini missions. Modeling of the propagation of radio waves is also available via ray tracing code using the latest magnetic and plasma models of Jupiter. These studies will continue and be expanded to include the environment at Saturn. Students would have direct access to these data as part of their education and research projects. Additionally, education and public outreach opportunities are available in connection with a NASA project called Radio JOVE, which focuses on science education using a simple radio telescope kit.