2018 Nobel Prize in Laser Physics

When I arrived at Bell Labs in 1988 on a postdoctoral appointment to work with Alastair Glass in the Department of Optical materials, the office I shared with Don Olsen was next door to the mysterious office of Art Ashkin.  Art was a legend in the corridors in a place of many legends.  Bell Labs in the late 80’s, even after the famous divestiture of AT&T into the Baby Bells, was a place of mythic proportions.  At the Holmdel site in New Jersey, the home of the laser physics branch of Bell Labs, the lunch table was a who’s who of laser science.  Chuck Shank, Daniel Chemla, Wayne Knox, Linn Mollenauer.  A new idea would be floated at lunchtime, and the resulting Phys Rev Letter would be submitted within the month…that was the speed of research at Bell Labs.  If you needed expertise, or hit a snag in an experiment, the World’s expert on almost anything was just down a hallway to help solve it.

Bell Labs in the late 80’s, even after the famous divestiture of AT&T into the Baby Bells, was a place of mythic proportions.

One of the key differences I have noted about the Bell Labs at that time, that set it apart from any other research organization I have experienced, whether at national labs like Lawrence Berkeley Laboratory, or at universities, was the genuine awe in people’s voices as they spoke about the work of their colleagues.  This was the tone as people talked about Steven Chu, recently departed from Bell Labs for Stanford, and especially Art Ashkin.

Art Ashkin had been at Bell Labs for nearly 40 years when I arrived.  He was a man of many talents, delving into topics as diverse as the photorefractive effect (which I had been hired to pursue in new directions), nonlinear optics in fibers (one of the chief interests of Holmdel in those days of exponential growth of fiber telecom) and second harmonic generation.  But his main scientific impact had been in the field of optical trapping.

Optical trapping uses focused laser fields to generate minute forces on minute targets.  If multiple lasers are directed in opposing directions, a small optical trap is formed.  This could be applied to atoms, which was used by Chu for atom trapping and cooling, and even to small particles like individual biological cells.  In this context, the trapping phenomenon was known as “optical tweezers”, because by moving the laser beams, the small targets could be moved about just as if they were being held by small tweezers.

In the late 80’s Steven Chu was on the rise as one of the leaders in the field of optical physics, receiving many prestigious awards for his applications of optical traps, while many felt that Art was being passed over.  This feeling intensified when Chu received the Nobel Prize in 1997 for optical trapping (shared with Cohen-Tannoudji and Phillips) but Art did not.  Several Nobel Prizes in laser physics later, and most felt that Art’s chances were over … until this morning, Oct. 2, 2018, when it was announced that Art, now age 96, was finally receiving the Nobel Prize.

Around the same time that Art and Steve were developing optical traps at Bell Labs using optical gradients to generate forces on atoms and particles, Gerard Mourou and Donna Strickland in the optics department at the University of Rochester discovered that optical gradients in nonlinear crystals could trap focused beams of light inside a laser cavity, causing a stable pulsing effect called Kerr-lens modelocking.  The optical pulses in lasers like the Ti:Sapphire laser had ultrafast durations around 100 femtoseconds with extremely stable repetition rates.  These pulse trains were the time-domain equivalent of optical combs in the frequency domain (for which Hall and Hansch  received the Nobel Prize for physics in 2005).  Before Kerr-lens modelocking, it took great skill with very nasty dye lasers to get femtosecond pulses in a laboratory.  But by the early 90’s, anyone who wanted femtosecond pulses could get them easily just by buying a femtosecond modelocked laser kit from Mourou’s company, Clark-MXR.  These types of lasers moved into ophthalmology and laser eye surgery, becoming one of the most common and most valuable commercial lasers.

Donna Strickland and Gerard Mourou shared the 2018 Nobel Prize with Art Ashkin on laser trapping, complementing the trapping of material particles by light gradients with the trapping of light beams themselves.

Galileo Unbound

In June of 1633 Galileo was found guilty of heresy and sentenced to house arrest for what remained of his life. He was a renaissance Prometheus, bound for giving knowledge to humanity. With little to do, and allowed few visitors, he at last had the uninterrupted time to finish his life’s labor. When Two New Sciences was published in 1638, it contained the seeds of the science of motion that would mature into a grand and abstract vision that permeates all science today. In this way, Galileo was unbound, not by Hercules, but by his own hand as he penned the introduction to his work:

. . . what I consider more important, there have been opened up to this vast and most excellent science, of which my work is merely the beginning, ways and means by which other minds more acute than mine will explore its remote corners.

            Galileo Galilei (1638) Two New Sciences

 

Galileo Unbound: A Path Across Life, the Universe and Everything (Oxford University Press) publishes today (Sept. 26, 2018). It explores the continuous thread from Galileo’s discovery of the parabolic trajectory to modern dynamics and complex systems. It is a history of expanding dimension and increasing abstraction, until today we speak of entangled quantum particles moving among many worlds, and we envision our lives as trajectories through spaces of thousands of dimensions. Remarkably, common themes persist that predict the evolution of species as readily as the orbits of planets. Galileo laid the foundation upon which Newton built a theory of dynamics that could capture the trajectory of the moon through space using the same physics that controlled the flight of a cannon ball. Late in the nineteenth-century, concepts of motion expanded into multiple dimensions, and in the 20th century geometry became the cause of motion rather than the result when Einstein envisioned the fabric of space-time warped by mass and energy, causing light rays to bend past the Sun. Possibly more radical was Feynman’s dilemma of quantum particles taking all paths at once—setting the stage for the modern fields of quantum field theory and quantum computing. Yet as concepts of motion have evolved, one thing has remained constant—the need to track ever more complex changes and to capture their essence—to find patterns in the chaos as we try to predict and control our world. Today’s ideas of motion go far beyond the parabolic trajectory, but even Galileo might recognize the common thread that winds through all these motions, drawing them together into a unified view that gives us the power to see, at least a little, through the mists shrouding the future.

 

To read more: Galileo Unbound: A Path Across Life, the Universe and Everything by David D. Nolte (Oxford University Press, Sept. 26, 2018). Available at Amazon.com.

 

Top 10 Books to Read on the History of Dynamics

Here are my picks for the top 10 books on the history of dynamics. These books have captivated me for years and have been an unending source of inspiration and information as I have pursued my own interests in the history of physics. The emphasis is on dynamics, rather than quantum and particle physics, although these traditional topics of “modern physics” have inherited many of the approaches of classical mechanics.

(1) Diacu, F. and P. Holmes (1996). Celestial encounters: The origins of chaos and stability. Princeton, N.J., Princeton Univ. Press.

Diacu and Holmes have written a clear, accessible and information-rich general history of the role that the solar system played in the development of dynamical theory, especially issues of the stability of the solar system.

(2) Pais, A. (2005) Subtle is the Lord: The Science and the Life of Albert Einstein: Oxford.

Pais has produced a masterpiece with his inside view of the historical development of Einstein’s ideas, for both special and general relativity. Through Pais’ story telling, it is possible to follow each turn in Einstein’s thinking as he proposed some of the most mind-bending ideas of physics.

(3) Thorne, K. S. (1994). Black holes and time warps : Einstein’s outrageous legacy. New York, W.W. Norton.

This book is an exuberant journey through the history of general relativity seen through the eyes of the recent Nobel Prize winner Kip Thorne. The book is full of details, many of them personal recollections as GR went from its early days through the “golden age” with John Wheeler located at the center of the motion.

(4) Schweber, S. S. (1994). QED and the men who made it: Dyson, Feynman, Schwinger, and Tomonaga. Princeton, Princeton University Press.

Schweber has produced a master work in the same genre as Pais, describing the development of QED in such moment-by-moment detail that you feel you are living the history itself. The description of Feynman’s stumble into the world of the “grown ups” at the Shelter Island and Pocono Conferences is priceless.

(5) Bacaer, N. (2011). A Short History of Mathematical Population Dynamics, Springer.

This compact little book is one of my favorites in terms of conciseness and completeness. It tracks a history that is little known inside physics, but which has taken on out-sized importance in the new era of complex systems where evolutionary dynamics describes diverse systems from neural networks to genetic algorithms.

(6) Gleick, J. (1987). Chaos: Making a New Science, Viking.

Gleick’s book is an absolute classic. This was one of my first introductions into the history of modern physics when I read it at the end of my post-doc position at Bell Labs in 1989. It has been a role model for my own dive into the history of physics.

(7) Cassidy, David C. (2010). Beyond Uncertainty : Heisenberg, Quantum Physics, and The Bomb. New York, NY, Bellevue Literary Press.

Cassidy’s sequel to his first book on Heisenberg (Uncertainty) is in the same master genre as Pais and Schweber. Reading page by page allows you to live the history yourself as Heisenberg struggled to escape from an overbearing father (and a disastrous doctoral defense) to make his mark on the world of physics.

(8) Jammer, M. (1989), The conceptual development of quantum mechanics. Tomash Publishers Woodbury, N.Y., American Institute of Physics.

Although dry and a dense read, this book is definitive. If you ever want to understand step-by-step how quantum mechanics evolved from the early thinking of Bohr to the advanced transformations of Dirac and Jordan, this is the book you want as a reference. It is endlessly deep and detailed.

(9) Crowe, M. J. (2007), Mechanics from Aristotle to Einstein: Green Lion Press.

This book is filled with lots of myth-busting about the early days of physics. It’s amazing that what we call “Newtonian Physics” was mostly not invented by Newton himself, but by others … even by his nemesis Leibniz!

(10) Coopersmith, J. (2010), Energy, the Subtle Concept: The Discovery of Feynman’s Blocks from Leibniz to Einstein: Oxford, Oxford University Press.

Coopersmith shows how the history of concepts of work and energy is surprisingly obscure. Newton himself made no mention of energy, and it took nearly 100 years for a clear picture of energy to emerge, despite its central role in dynamical systems.

 

There are many wonderful review articles in review journals. A few of my favorites are:

Aubin A. and Dahan Dalmedico, D. (2002). “Writing the History of Dynamical Systems and Chaos: Longue Durée and Revolution, Disciplines and Cultures”. Historia Mathematica, 29, 273-339.

Ginoux, J. M. and C. Letellier (2012). “Van der Pol and the history of relaxation oscillations: Toward the emergence of a concept.” Chaos 22(2).

Gutzwiller, M. (1998), Moon-Earth-Sun: The oldest three-body problem, Reviews of Modern Physics, vol. 70, No. 2

Jenkins, A. (2013). “Self-oscillation.” Physics Reports-Review Section of Physics Letters 525(2): 167-222.

Morgan, G. J. (1998). “Emile Zuckerkandl, Linus Pauling, and the molecular evolutionary clock, 1959-1965.” Journal of the History of Biology 31(2): 155-178.

 

 

Galileo Unbound: The Physics and History of Dynamics

Welcome to Galileo Unbound: The History and Physics of Dynamics. This is the Blog site where you can find the historical background and the physical concepts behind many of the current trends in the physics of complex systems. It is written at the level of college undergraduates in fields of study like science or engineering. Advanced high school students should be able to find little gems here, too.

The topics here will fall under two headings that mirror my two recent books: Introduction to Modern Dyanamics (Oxford University Press, 2015) and Galileo Unbound (Oxford University Press, 2018). The first is a college junior-level physics textbook describing the mathematical details of modern dynamics. The second is a general interest book on the historical development of the same ideas. The physical concepts in both books will be expanded upon in this Blog at a general level of understanding. I hope you enjoy the broad range of topics that will appear here.

Good company in a journey makes the way seem shorter. — Izaak Walton