The 2009 Nobel Prize in Physics was awarded for developments in fiber optics, so it seems appropriate to recall Michigan’s important contributions to the field.
Gastroscopes and endoscopes are used by physicians to look inside the human body. These were originally fashioned as a set of lenses mounted in tubes of limited flexibility, so their clinical use had many constraints. Alternatives were needed.
Even before the 1920s, scientists recognized that images, as mosaics, could be transmitted over a well-ordered bundle of optical fibers. Knowing that long fibers thinner than a human hair could be drawn from a hot melt, different groups explored the possibility of using a bundle of many fibers to make a flexible gastroscope of small enough diameter to be easily swallowed. Some advances were made but there remained major obstacles to success:
--First, the clarity of a mosaic image depends on having each fiber optically isolated from its neighbors, a requirement difficult to meet since cross-talk tends to occur when simple fibers touch one another.
--Second, a mosaic must have thousands of elements to provide a useful image. The fidelity of that image depends on having the same ordering of those tiny fibers at each end of the gastroscope.
In the spring of 1955 Basil Hirschowitz, a young M.D. gastroenterology resident in the medical school, urged Michigan physicists Professor Wilbur Peters and his undergraduate student Larry Curtiss to undertake the challenge of making a fiber optic gastroscope.
Larry Curtiss overcame the problem of optical cross-talk by placing a rod of high-index glass within a tube of glass that had a lower index of refraction. Heating this to near melting temperature, he was able to draw out a long, thin fiber in which light could propagate without actually reaching the outer, clad surface of the fiber. Larry Curtiss and Professor Peters then assured the correct ordering of mosaic elements by winding thousands of turns of fiber into a coil. Then, having seized a short portion of that coil, they sliced through the seized portion. The result was stunningly successful; they had made a fiber bundle that had high fidelity, minimal cross-talk, and extraordinary flexibility.
By December of 1956, they had learned the technology well enough to assemble 40,000 fibers into a bundle about one cm in diameter and one meter long. They covered that bundle with a rubber tube and Dr. Hirschowitz, after swallowing it himself as a test, first used the fiber optic gastroscope on a patient on February 18, 1957.
The astonishing success of the Michigan fiber optics research led to important medical applications in diagnostics and minimally invasive surgery advances that we take for granted today.
The Michigan researchers did apply for patents that related to the use of fiber optics to transmit images. It is regrettable that they made no claims related to the use of fibers for the optical transmission of data.
Dr. Hirschowitz went on to a very successful career on the faculty of the Medical School at the University of Alabama, where he pioneered in the development of clinical applications for the new gastroscope. Larry Curtiss started graduate school at Harvard, but was soon drawn to the optical industry by the demands for his expertise. Professor Wilber Peters continued directing research with his graduate students at Michigan. In 1961 he, together with Michigan Physics Professor Peter Franken, Alan Hill (an undergraduate!) and Physics Professor Gabriel Weinreich, devised the fundamental experiment that first generated optical harmonics.