The 2,449th Meeting of the Society

November 19, 2021 at 8:00 PM

Powell Auditorium at the Cosmos Club

Microchip Accelerators

Laser-driven particle accelerator-on-a-silicon-chip

Robert L. Byer

Kenan Professor of Applied Physics
Stanford University

About the Lecture

To reach the energies required to explore new regimes of physics, particle accelerators have to be extremely large.  They are extremely complex, costly undertakings that require international support over long periods of time to build and to operate.  The Large Hadron Collider, currently the world’s largest and most powerful accelerator, is 27 kilometers in circumference!  And it required decades of planning, billions of dollars, coordination and cooperation of thousands of scientists, engineers and suppliers, and sustained support from a dozen countries.  While the LHC has been and continues to be a great success, reaching substantially greater energies than it can achieve will be prohibitively difficult and costly with conventional accelerator technology.  And current accelerator technologies are too large, cumbersome and expensive to provide the smaller-scale accelerators for uses in medicine and industry.

A great deal of effort is being devoted to developing more compact, less expensive technologies.  One approach is the dielectric laser accelerator (DLA).  It uses an ultrafast IR laser to deliver energy to electrons inside a microchip-scale device.  The approach has the potential to dramatically shrink particle accelerators, which would enable ultrafast tabletop electron diffraction and microscopy experiments and tunable x-ray sources.  The approach also holds promise for the construction of particle accelerators for the exploration of physics beyond the reach of the LHC and other very large conventional accelerators under consideration.

This lecture will describe an international effort that is now underway to develop a laser-driven accelerator integrated on a silicon photonics platform – “accelerator on a chip”.  It will describe the technology, what has been achieved to date and the prospects for further development in the near term and into the following decades.

Selected Bibliography

(1)  England et al. (2021):  Microchip accelerators; Physics Today, Vol 74, No. 8, pp42 et seq. 

(2)  Sapra et al. (2020):  On-Chip Integrated Laser-Driven Particle Accelerator; Science Vol 367, Issue 6473, pp. 79-83.

(3)  England et al. (2014):  Dielectric Laser Accelerators; Rev Mod Phys Vol 86, pp 1337 et seq. 

About the Speaker

Robert L. Byer is William R. Kenan Professor in the Department of Applied Physics at Stanford University.  He also is a member of the National Ignition Facility.  In a long and distinguished career he has severed in many leadership roles, including, at Stanford, Vice Provost and Dean of Research, Chair of the Department of Applied Physics, Director of the Ginzton Laboratory and Director of the Hansen Experimental Physics Laboratory.  He was a founding member and served as Chair of the California Council on Science and he served on the Air Force Scientific Advisory Board.

Robert’s research focuses on lasers and nonlinear optics.  His current research projects include the development of precision laser measurements to support the detection of gravitational waves and the development of laser accelerators “on a chip”.  He has made many contributions to laser science and technology, including the demonstration of the first tunable visible parametric oscillator, the development of the Q-switched unstable resonator Nd:YAG laser, remote sensing using tunable infrared sources, and precision spectroscopy using Coherent Anti Stokes Raman Scattering.

Robert is an author on more than 551 publications, including over 470 in technical journals, and he speaks frequently at technical conferences.

Among many honors and awards, Robert is a Charter Fellow of the National Academy of Inventors, the recipient of numerous prizes, awards and medals from professional societies, including the IEEE, the Optical Society of America, and the American Physical Society, and he is a Fellow of the AAAS, the American Physical Society, the Optical Society of America, and the California Council on Science and Technology.

He earned his BS in Physics at UC-Berkeley, and his MS and PhD in Applied Physics at Stanford University.