November 2, 2010
Definitions don’t seem to come easy to scientists. Consider Pluto’s planethood, or the question of what constitutes life. More recently, the definition debate has even stymied how to describe a laser.
Sure, the acronym LASER stands for Light Amplification Stimulated Emission of Radiation. But fifty years of studying amplified light sources has moved the device far beyond simple laser pointers, so much so that a large consortium of scientists could only agree that a laser is, “hard to define, but I know one when I see one,” said Warren Warren, chair of Duke’s chemistry department and a speaker at the 2010 Fitzpatrick Institute for Photonics, or FIP, symposium.
The event, held Oct. 27-28, featured talks, poster sessions and themed lab visits on Frontiers in Photonics: Science and Technology. It also celebrated the 50-year anniversary of the laser’s discovery and the 10-year anniversary of Duke’s photonics institute.
Warren, part of the Technical Advisory Committee for LaserFest, a yearlong celebration of the 50th anniversary of the laser, said dozens of scientists weighed in as the committee tried to develop a satisfactory definition of the laser for the LaserFest Website, laserfest.org. "Up to about three months ago, on no place on the site did it say what a laser was."
LaserFest.org, after considerable scientific discussion, now defines the laser as a “device that strengthens light waves.” Some lasers have a well-directed, very bright beam with a very specific color; some have extremely short pulses. “The key feature is that the amplification makes light that is very well defined and reproducible, unlike ordinary light sources such as the sun or a lamp,” the site states.
Warren added that a definition for Congress might also include "economic engine." Ten billion dollars in laser research has enabled four trillion in technology, he said.
He, along with thoracic surgeon Thomas D’Amico and biomedical engineers Joseph Izatt and Cynthia Toth, then went on to describe the laser technologies they are developing at Duke to diagnose and treat skin, lung and esophagus cancer as well as macular degeneration and other eye diseases.
The second day of the symposium also highlighted biological and medical uses of lasers. Biomedical engineer Adam Wax, neurosurgeon Gerald Grant and radiologist James Provenzale described technologies they are testing to detect cancer cells during surgery.
The 1999 Nobel Laureate in Chemistry, Ahmed Zewail, director of the Center for Physical Biology at Caltech University, provided the symposium's keynote lecture. Progress and peace would come with greater global collaboration and cooperation, beginning in science, he said. And quite possibly, with those debatable definitions.