Home https://server7.kproxy.com/servlet/redirect.srv/sruj/smyrwpoii/p2/ Science https://server7.kproxy.com/servlet/redirect.srv/sruj/smyrwpoii/p2/ Arthur Ashkin, Nobel Prize-winning physicist who captures light molecules, dies at 98

Arthur Ashkin, Nobel Prize-winning physicist who captures light molecules, dies at 98



Dr. Ashkin became the oldest Nobel laureate in history when he won the Physics Prize in 2018, at the age of 96, for inventing optical tweezers more than three decades earlier. He had long ago “refused to worry” about the awards, he said, and saw that his record was broken just a year later when John B. Goodenow won the Nobel Prize in chemistry at the age of 97.

A longtime researcher at Nokia Bell’s current laboratory in New Jersey, Dr. Ashkin was fascinated by the often overlooked aspect of light, which exerts a relatively weak force known as radiation pressure. After the invention of the laser in 1

960, he believed he could use the device to push a microscopic ball with nothing but a densely focused beam of light.

To his delight, the forces in the laser actually pushed the ball into the center of the beam and held it there, holding it in place. His breakthrough, reported in a 1970 article published despite initial skepticism from Bell Labs, was the first step toward creating optical tweezers.

The tool uses “laser fingers”, as the Nobel Prize committee put it, to grab atoms, viruses, bacteria and other living cells, and is credited with paving the way for progress, including the development of a blood test for malaria and cholesterol-lowering drugs. .

“Optical tweezers were not an invention, but a surprise,” former Ashkin colleague David G. Greer, a physicist at New York University, told the New York Times in 2018. “It was a new thought for science, this light can pull . This is revolutionary. “

Dr. Ashkin has shown that a vertical laser beam can be used to levitate microscopic particles and has partnered with colleagues such as Stephen Chu, a future energy secretary and Stanford professor, to demonstrate that atoms can be slowed to crawl. and contained in a field of laser light, which Dr. Ashkin proposed in his 1970 report.

“To do real physics, you have to go to extremes,” he told the New York Times in 1986 after the Bell Labs team managed to use seven lasers to cool and capture atoms in a field known as “optical molasses”. Their experiments were led by Chu, who was awarded the Nobel Prize in 1997. Dr Ashkin said he felt “missed” by the honor.

In a telephone interview, Chu called Dr. Ashkin a “pioneer in particle capture,” whose subsequent work on capturing living things surprised many of his peers. In 1987, Dr. Ashkin reported in two separate articles that he used infrared lasers to capture and move viruses, bacteria, and single cells, announcing the arrival of optical tweezers as a new tool for scientists studying microbes and cell structures.

“Unlike many other scientists, he is able to think about things that are clear,” Chu said. Optical tweezers, he added, had allowed him to stretch and examine DNA and allowed Stanford biophysicist Stephen M. Block to study the “molecular engine” that allows E. coli to descend and swim. “It was a new insight into biology. . . the new child in the block, ‘said Chu. “The precision of this technique very quickly became good enough to measure piconeuton forces and nanometer distances.”

For his part, Dr. Ashkin pioneered what he called a type of “intracellular surgery” in which researchers could use laser traps to capture and move large organelles such as nuclei and chloroplasts into the cell. He later said that he and his colleague Joe Dziedzic initially trapped living beings by accident after leaving an experiment conducted overnight and found that the bacteria were trapped inside.

“When I described capturing living things with light,” he recalls, “people said, ‘Don’t exaggerate, Ashkin.’ Soon, he told Business Insider last year, colleagues had a different reaction: “Oh, you have to see this – Ashkin’s trap! He catches bugs! “

Arthur Ashkin was born in Brooklyn, New York, on September 2, 1922, to a family of Jewish immigrants from Eastern Europe. His father founded a dental laboratory in Manhattan, and his parents acquired a children’s encyclopedia called the Book of Knowledge, which conquered a young art by introducing it to science.

Dr. Ashkin worked in a lab at Columbia University during World War II, developing a magnetron – a vacuum tube that generates microwaves – as part of an army radar program. He graduated from Colombia with a degree in physics in 1947.

On the advice of his older brother Julius, who helped develop the atomic bomb as a researcher on the Manhattan Project, he continued to study nuclear physics, earning a doctorate in 1952 from Cornell University.

His brother cast a long shadow – “I was known as ‘Ashkin’s brother Ashkin,'” he later said, “and the younger Ashkin decided to change fields by joining Bell Telephone Laboratories in 1952 to study microwaves.” About a decade later, he began focusing on lasers and nonlinear optics and worked in a laboratory in Holmdel, New Jersey, before retiring in 1992.

“He was very generous. On a scientific level, he would give people ideas and not try to take credit – he probably took less credit than he deserved, “said in a telephone interview his friend Rene-Jean Essiambre, a physicist from Bell’s laboratories. “It may have been a reason he didn’t win the Nobel Prize earlier. Everyone who has worked with him has received high-quality and wonderful ideas, which is not so common when you do high-level science. People tend to keep their ideas close to them. “

Dr. Ashkin shared the Nobel Prize with Gerard Moore and Donna Strickland, who developed a way to generate “intense, ultrashort optical pulses” with a laser. He was also elected to the National Academy of Engineering and the National Academy of Sciences and was inducted into the National Inventors Hall of Fame in 2013.

Among the survivors are his 65-year-old wife, Alain Ashkin, a fellow Cornell graduate who later taught chemistry in high school; three children, Judith Herscu and Daniel and Michael Ashkin; five grandchildren; and two great-grandchildren.

Dr. Ashkin continued to work from his home lab long after retiring from Bell Labs. Faced with catastrophic climate change, he is interested in solar energy and is working on a low-cost energy document that Essiambre is trying to complete.

In an interview last year, Dr. Ashkin told Business Insider that he believed his new method of producing cheap energy would “save the world” – and was worthy of a second Nobel Prize. “I’ll win too,” he said.


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