By Patricia Daukantas
I can’t let my coverage of FiO/LS end without mentioning the wonderful talk that OSA Honorary Member Arthur Ashkin gave at the special symposium organized in his honor.
Ashkin, now 88 years old and retired from Alcatel-Lucent/Bell Laboratories (U.S.A.), pioneered the notion of moving microparticles with laser light, back in the days when lasers were the new thing on the lab bench. His work formed the basis for optical tweezers and, eventually, the atom-cooling and laser-trapping work that garnered three other OSA Honorary Members their Nobel Prize in 1997.
In his autobiographical speech, Ashkin--who still has traces of the accent of his native Brooklyn, N.Y.--showed his warm and sometimes mildly self-deprecating humor. Yes, he said, he holds degrees from “all these fancy schools” like Columbia and Cornell universities, but it took him seven years just to get his bachelor’s degree.
That wasn’t entirely of his own doing. As he entered Columbia, World War II was starting and the university, whose physics department had people like Sidney Millman, Willis Lamb and Polykarp Kusch, founded a radiation laboratory with, as Ashkin put it, “all this new equipment free from the government.” Millman taught the new undergraduate about magnetrons – “glass, brass and sealing wax” – and then Ashkin got drafted at age 19.
“I’m a sophomore, how important can I be to the war effort?” Ashkin asked rhetorically. But the folks at Columbia got him into the Army’s enlisted reserve, so that he could work as a staff member, and he eventually built a megawatt magnetron.
Once Ashkin got to Cornell as a graduate student, he said, he took no solid-state physics or optics courses. “All I took was nuclear physics because there were all these guys from Los Alamos [the Manhattan Project, which built the first nuclear weapons],” he said. He took the first quantum mechanics class taught by the then-future Nobel Prize winner Richard P. Feynman. Ashkin added: “The stories I could tell, if I had the time…”
Once hired at Bell Labs, he was told he could do anything he wanted to do, but he still ended up working on microwave tubes for a while. “At Bell Labs they wanted you to do great work, but you had to find your own way,” he said.
In the late 1960s, Ashkin attended a talk about “runners” and “bouncers,” or tiny balls moving around due to heating. That got him thinking about radiation pressure, and he started thinking about moving even tinier particles with the light from laser beams, and then experimenting in earnest.
By the time Ashkin was writing his first paper on the subject, he was wondering whether the laser beams could trap atoms, molecules and microscopic living things. “So I put all that into the paper and got credit for it,” he added. His first experiments with trying to move bacteria around killed them--he dubbed it “opticution”--but eventually he and his colleagues learned how to keep them alive while moving them with infrared beams.
You can read more about Ashkin’s pioneering efforts in a March 2010 feature article in OPN.
Like a good entertainer, Ashkin knows how to leave his audiences wanting more. He wound up his talk by saying that during his 15-year retirement, he has been experimenting with solar power, and he thinks he has found away of getting energy from the Sun more cheaply than burning fossil fuels.“I’m writing a paper for Science, and if I tell you about it they won’t publish it,” he concluded. “So stay tuned.”
The Newest OSA Honorary Member
At its meeting during FiO/LS, the OSA board of directors selected James P. Gordon as the Society’s newest Honorary Member. Regular readers of OPN may recall his article for the May 2010 issue of OPN--the special “Lasers at 50” issue--in which he described his work on the first maser with another OSA Honorary Member, Charles H. Townes.
2010-10 October, Applied optics, Biomedical optics, Frontiers in Optics, Optics history