For Immediate Release
January 24, 1997

LASER DYNAMICS LABORATORY OPENS NEW POSSIBILITIES FOR STUDY OF PHOTONIC INTERACTION WITH MATERIALS

A new research laboratory launched recently at the Georgia Institute of Technology will use the latest in laser analytical techniques to study how photons interact with materials of all types, including the human body.

The Laser Dynamics Laboratory, supported in part by funds from the National Science Foundation (NSF), will provide a shared resource for researchers, encourage collaboration across disciplines and facilitate the use of laser spectroscopic techniques in new areas of study, said Director Dr. Mostafa El- Sayed.

Researchers study the interaction of photons with materials in Georgia Tech's Laser Dynamics Laboratory.

"We are establishing collaborative programs in many research areas in which lasers interface with materials," he explained. "We know about photons and what they will do. We want to extend that knowledge into other applications that are helpful to us and to other researchers. This combination of expertise from different areas can lead to many new developments."

Part of Georgia Tech's School of Chemistry and Biochemistry, the Laser Dynamics Laboratory operates a series of laser systems and related analytical equipment configured for use in spectroscopic techniques. The equipment can study phenomena that take place in as short a time scale as 100 femtoseconds -- the amount of time required for light to travel the width of a human hair.

Such analytical techniques can be used to investigate a wide range of phenomena, including the dynamics of molecular dissociation, energy relaxation and transformation; molecular mechanisms of the primary processes of photosynthesis, and electronic and energy transport in various materials ranging from nanoparticles to disordered solids to photobiological systems.

El-Sayed said the facility would be of interest to researchers studying the detailed structural changes in molecules or materials following linear or nonlinear laser excitation in the 100 femtosecond to millisecond time domain. The laser- induced changes can be followed by observing the optical absorption, fluorescence, Raman or infrared spectra of the transients.

At Georgia Tech, the new facility could boost existing research into the properties of optical, electro-optical and nonlinear optical materials -- key technologies in developing new generations of fast optical switches, new memory devices, and techniques useful in interfacing high-bandwidth optical systems to computers.

"This adds to Georgia Tech a facility that can measure the properties of materials using lasers, which is one of the most important capabilities today," El-Sayed explained. "As we get deeper and deeper into studying materials and their application to the field of communications, this will become more important."

But while study of inorganic materials may provide the laboratory's primary near-term benefit, he believes laser spectroscopic techniques also offer great long-term potential in the diagnosis of human disease processes. There, unique "signatures" of cancerous tissue or disease organisms could provide physicians with immediate diagnosis without the need for time-consuming laboratory clinical analytical techniques.

El-Sayed expects the new research laboratory, built with NSF and Georgia Tech support, will encourage collaboration and help researchers make efficient use of the costly laser equipment, which is already used extensively in his own research program. This availability could also encourage research into new areas where these analytical techniques are helpful to understanding complex issues.

"At a time when national resources are limited, a facility like this will help stretch the ability to researchers to get their work done and allow them to study these phenomena without having to invest in their own laser equipment," he explained.

Systems and techniques available at the laboratory include transient optical absorption spectroscopy, time-resolved Raman Spectroscopy, time-resolved IR spectroscopy (TRIR) and time- resolved Fourier Transform Infrared (TRFTIR) spectroscopy, and fluorescence spectroscopy and time-correlated single photon counting.

Available equipment includes:

• A Clark-MRX Amplified Ti:sapphire system which pumps two Quantronix TOPAS-POP, producing two femtosecond pulses each with a wavelength that can be changed independently from the UV to the infrared range.

• An Antares/Satori coherent picosecond system and a SpectraPhysics MOPO 730 nanosecond laser that can provide wavelengths in the UV to the infrared range.

• A flash photolysis system combining laser pumping and Xenon flash or CW lamps for time-resolved spectral measurements in the nanosecond to millisecond time scales.

• A Bruker time-resolved FTIR system is available to measure changes in IR spectra in the nanosecond to millisecond time range.

The laboratory was formally inaugurated with a symposium and open house November 22-23. El-Sayed holds the Julius Brown Chair in chemistry, and is also editor-in-chief of the Journal of Physical Chemistry, a publication of the American Chemical Society.

RESEARCH NEWS AND PUBLICATIONS OFFICE
Georgia Institute of Technology
75 Fifth Street, N.W., Suite 100
Atlanta, Georgia 30308

MEDIA RELATIONS CONTACTS: John Toon (404-894-6986)
E-mail: john.toon@edi.gatech.edu;
FAX: (404-894-4545)

TECHNICAL CONTACTS: Dr. Mostafa El-Sayed (404-894-0292);
Internet: mostafa.el-sayed@chemistry.gatech.edu.

VISUALS: Color slide showing researcher working with visible light lasers.

WRITER: John Toon