Arthur Ashkin, Nobel Laureate and Pioneer in Optical Trapping, Dies at 98

Arthur Ashkin, Nobel laureate, has died at the age of 98. Ashkin, known for his pioneering work in the creation of optical tweezers, was the first to observe optical gradient forces on atoms, the first to perform laser cooling of atoms known as “optical molasses,” and the first to observe optical trapping of atoms. His work in the area of optical trapping and manipulation of small dielectric particles using optical gradient forces would become the foundation for the future of physics research in ultracold and trapped atoms.

Ashkin studied physics at Columbia College and received a B.A. in physics in 1947 and a Ph.D. in nuclear physics from Cornell University in 1952.

He worked at the Columbia Radiation Lab from 1942 to 1945 while in the Army, and at AT&T Bell Laboratories from 1952 to 1991. At Bell Labs, Ashkin researched microwaves, nonlinear optics, and laser trapping. With colleagues he made the first observation of continuous-wave (CW) laser harmonic generation and CW parametric amplification; discovered the photorefractive effect; and initiated the field of nonlinear optics in optical fibers.

Ashkin extended this work to the trapping and manipulation of living material such as bacteria, viruses, and cells; the laser technique for holding material in place became known as “optical tweezers.” Ashkin used the approach to explore the interior of a cell, manipulating its inner structures and laying the foundation for new and enhanced understanding of normal and diseased states in the human body.

The ability to cool and trap atoms has led to spectacular advances in basic science, such as the creation of Bose-Einstein condensates in atomic vapor.

For his pioneering work in optical trapping, Ashkin was awarded the Nobel Prize in physics in 2018. Ashkin was awarded half of the prize while the other half was shared between Gérard Mourou and Donna Strickland. Ashkin was the author of Optical Trapping and Manipulation of Neutral Particles Using Lasers, and he held 47 patents.

In addition to the Nobel Prize, awards and honors recognizing his scientific contributions included election to the National Academy of Engineering and the National Academy of Sciences; The Optical Society’s (OSA) Frederick Ives Medal/Jarus W. Quinn Endowment (1998); Charles Hard Townes Award (1988); APS’s Joseph F. Keithley Award for Advances in Measurement Science (2003); the Rank Prize in Opto-Electronics (1993); the IEEE Photonics Society’s Quantum Electronics Award (1987); and the Harvey Prize for physics (2004).

Ashkin was named an OSA Fellow in 1983, and was also a fellow of the APS, IEEE, and AAAS. In 2009, he was named an honorary member of The Optical Society for his pioneering work on optical trapping and the development of optical tweezers.