By Patricia Daukantas

Before the end of this month – which has featured my article on “Lasers in Ophthalmology” as the OPN cover story – I wanted to mention at least one OSA Fellow who helped to develop laser-assisted in situ keratomileusis, or LASIK.

This ophthalmic surgical procedure is not exactly new – it’s advertised all over the radio in my metropolitan area, and OPN published several articles about the technology within the past 10 years. But one OSA Fellow, James J. Wynne, and four of his colleagues were, just this month, awarded the Rank Prize for Optoelectronics for their application of excimer laser surgery to refractive correction of the cornea.

Wynne, who is with IBM Corp., was one of three winners of the 2004 R.W. Wood Prize from OSA for their invention of pulsed ultraviolet laser eye surgery. The trio was also inducted into the U.S. National Inventors Hall of Fame. The back story of their work in laser tissue ablation is fascinating and a little unusual.

In 1981, according to IBM’s Inventors Hall of Fame press release, Wynne, Rangaswamy Srinivasan and Samuel Blum were considering how to use ablative photo-decomposition as a surgical technique. “At Thanksgiving dinner that year, Srinivasan decided to run the first experiment on the turkey bone sitting before him,” the statement reads. “He brought the turkey bone to work, and the IBM team irradiated the cartilage on the end of the bone with both an ultraviolet excimer laser and a conventional, green laser. Looking at the startling difference between the clean incision produced by the excimer laser and the charred, damaged region produced by the green laser, the IBM team realized that they had uncovered a new phenomenon, which became the basis of their invention.”

Wnne graduated from Great Neck (N.Y., U.S.A.) High School 50 years ago, just as the first laser was fired up. He tells his classmates that he got his Ph.D. in nonlinear optics at Harvard under OSA Honorary Member Nicolaas Bloembergen. The “best personal reward” he got from his laser-related research was the surgery his formerly myopic and astigmatic son had a few years ago – the son now has 20/15 vision.

The LaserFest website has a fascinating profile of Wynne, with more details about the Thanksgiving-turkey experiments with the 193-nm laser. You can also see a snapshot of Wynne with his trusty Volkswagen Beetle, known as “Laserbug.”

2010-02 February opthalmology

By Patricia Daukantas

A trio of scientists – including the current U.S. secretary of energy, OSA Honorary Member Steven Chu – has verified one prediction of Albert Einstein’s general theory of relativity with 10,000 times more accuracy than previous experiments yielded.

The scientists used a cesium atom interferometer to test the gravitational redshift predicted by Einstein. The results appear in the Feb. 18, 2010, issue of Nature.

The scientists obtained the data for this week’s article more than 10 years ago, when Chu was still at Stanford University (U.S.A.). At that time, Chu, who shared the 1997 Nobel Prize in physics for developing laser-cooled atom traps, and his colleagues were measuring the acceleration of gravity, according to a news article in Nature (subscription required). One of Chu’s then-graduate students, Achim Peters, now heads the optical metrology group at Humboldt University in Berlin (Germany).

Much later, a former student of Peters who also worked in Chu’s Stanford group -- Holger Müller, now an assistant physics professor at the University of California, Berkeley (U.S.A.) – realized that the data from the late-1990s experiment might yield a high-precision test of gravitational redshift. He contacted Chu, who has been juggling his work on the study with his leadership of the Cabinet-level department with a $24.1-billion budget.

The part of Einstein’s theory that Müller, Peters and Chu tested involves the slowing down of clocks in a gravitational potential U by a factor of 1 + U/c², where c is the speed of light. (That “slowing down” is relative to a clock outside the gravitational potential, of course – everything’s relative!) The previous experiment, which involved taking a hydrogen maser clock on a rocket ride in 1976, found that Einstein’s prediction held true to a precision of 7 × 10^–5. By studying the rise and fall of cesium atoms in a laser trap and measuring the slight phase differences among the frequencies of the atoms, the researchers improved the accuracy of the redshift prediction to 7 × 10^–9. 

For more information, read the Berkeley press release here.

2010-02 February gravity, laser trapping, atomic clock, steven chu

By Patricia Daukantas

Last week my colleagues and I finished up the final round of proofreading on the March issue of OPN and sent it off to the printer. We also held our annual planning meeting for OPN, with invitees from all around the United States as well as from Canada, France, Mexico, Russia, Turkey and Australia.

None of this was particularly unusual … except that the city of our headquarters, Washington, D.C., was sitting underneath more snow than it ever has received since modern meteorological recordkeeping began. According to the Capital Weather Gang blog on WashingtonPost.com, seasonal snow totals (including a December snowstorm) stand at 142 cm at Reagan National Airport, 186 cm at Dulles International Airport and 203 cm at Baltimore’s BWI Marshall Airport.

If the advances in fiber-optic telecommunications hadn’t happened over the last 20 years, collaborating on the magazine pages from home, as well as teleconferencing with advisers who weren’t able to get to Washington in person, would have been either impossible or prohibitively expensive.

So, here’s a salute to all of our OPN readers and OSA members who have contributed to the world of optical fiber communications. Thank you very much! And because of you, everyone will get to enjoy the March OPN as if no bad weather ever happened here.

2010-02 February fiber optics, telecommunications, osa