Front Matter

Rain and a rainbow in the Kalahari Desert, Botswana. Permission obtained through Shutterstock. The rainbow would have been a source of wonder to our earliest Homo sapiens ancestors in Africa 300 000 years ago. Attempts to understand the science of the rainbow began at least with Aristotle, and progressed through Newton 2000 years later. To this day, the rainbow remains an inspiration and a metaphor for unity.

In writing this book, I am indebted to a large number of people. My wife Karen, a good writer and editor, has helped me with the flow of the text and with the grammar. College physics students Eleda Fernald at Oberlin College and Todd Cheng at Case Western Reserve University provided critical readings of early drafts from the perspective of college undergraduates—the target audience. They pointed out things obvious to the writer, but less so to a student not so familiar with the many aspects of light, and these areas were improved. Their feedback also stimulated some important structural changes. Esteemed long-time GE colleagues, now retired—Rolf Bergman, Mark Duffy, Dick Hansler, Terry McGowan, Kemp Smith, and Tom Soules—provided helpful inputs. Collectively, they reviewed later drafts, suggested additional aspects of light to include, and expanded my list of references. Ken Kowalski, who has taught a broad non-mathematical seminar titled “Light” at Case, once invited me as a guest lecturer. He introduced me to Zajonc's book, and gave me some helpful feedback related to Planck and Einstein. Carol Derov, whose long career was in the area of color as it relates to design in general, and to the paint industry in particular, spent a very helpful session with me. She broadened my appreciation of color from a completely different perspective than my own. Dale Hilton has had many helpful conversations with me regarding the role of light and color in art and design. She also stimulated my widespread use of color images. Nora Murphy, who teaches classical languages, reinforced that the word for light in New Testament Greek has both a literal meaning and a metaphorical meaning, just as it does in English. Roger Williams was extremely helpful with aspects of writing and publishing during a previous book venture, and many of his lessons have stuck with me.

This story of light grows out of a lifelong fascination with the subject—as a student, as a professional, and as an always curious observer. One might say, metaphorically, that light is in my blood. While writing a personal memoir for my family, it became suddenly obvious that the big story of light—history, science, applications, and human impact—is nowhere captured in one place. Hence, the purpose of this book is to allow anyone involved with light to see the bigger picture at a macroscopic level. The book is especially directed at STEM students who have already encountered the core physics of light material in Chap. 4.

My father, Thomas Wendell Dakin, Ph.D., was the perfect father for me. He was an internationally recognized authority in the field of electrical insulation, having developed the Arrhenius relationship as a tool for accelerated testing of insulation systems. He eventually received the IEEE Lamme Medal for this work, and has an award named in his honor in the field of electrical insulation. Starting around elementary school, he taught me many practical hands-on skills related to light, photography, the darkroom, electricity, and woodworking. These were so helpful to me throughout life as an experimental physicist and as a homeowner. As I was entering middle school, he gave me a copy of the book The Universe of Light by Sir William Bragg. Reading it, I became familiar with the phenomena in Chap. 3 in a visceral way years before I began learning the core physics course material of Chap. 4.

My mother, Theodora Letta Peck Dakin, M.D., eventually became a medical doctor, a general practitioner, after being discouraged from pursuing chemistry in college. Besides setting a wonderful example in many ways, she gets special credit for nurturing my love of reading from an early age. Without this, I might not have so much enjoyed reading the books about light that have helped me to see the big picture presented here.

Professor Norman Ramsey, my academic advisor at Harvard and later Nobel Laureate, spent inspirational time telling me about his hydrogen maser, which now makes modern GPS possible. I shall never forget time with Gerald Holton, another Harvard professor and an Einstein scholar. Following Einstein's death, Holton had played a lead role in organizing Einstein's papers. He spent an evening with several of my STEM colleagues and me, helping us to understand how truly deep a thinker Einstein was. Holton introduced us to Einstein's skepticism about quantum mechanics, and to the Einstein–Podolsky–Rosen paradox.

At Princeton, Professor Eugene Wigner, Nobel Laureate, was especially kind to me and the other graduate students. He had a treasure trove of great stories from his association with Einstein and others, and through his work on the Manhattan Project. Einstein had been based at the Institute for Advanced Study in Princeton from 1933, the year in which he emigrated from Nazi Germany to the USA, until his death in 1955. Wigner had, in fact, been at a historic meeting with Einstein and Szilard that led to the Einstein–Szilard letter to President Franklin Roosevelt. This letter, in turn, led to the Manhattan Project. To us, Wigner was just an extremely warm, friendly, and engaging professor. During the oral exams, one needed only to look into Wigner's eyes to be calmed and see the answers to the questions.

I am equally indebted to Professor Eric Rogers at Princeton, whom I assisted in teaching his popular introductory physics course aimed at premedical students. Eric was a master of the lecture demonstration. Some of his favorite demonstrations often drew large crowds from the community. I shall never forget his sequence of lectures on the role that the wandering stars played in the development of science. My copy of the book A History of Science and its Relation to Philosophy and Religion by W. C. Dampier was a parting gift from Rogers.

Around 1969, I went to my first winter meeting of the American Physical Society. There I heard a talk on quarks by already legendary Richard Feynman, Nobel Laureate. I was mesmerized. Eventually Feynman, now deceased, had become as close to being a “rock star” as a physicist ever gets. A few years later, in 1973, I attended a two-week course given by Feynman at the University of Hawaii. Later I found him citing a paper I had co-authored.

During my postdoctoral years at the Stanford Linear Accelerator Center (SLAC), I had the good fortune to work with Professor Martin Perl and Professor Burt Richter, to be part of their Nobel Prize winning discoveries, and even to be listed as coauthor in their key papers. I had the equally good fortune at SLAC to have great contemporaries to work with, most notably Gary Feldman. I was further able to continue the work at SLAC during the two years that I taught at the University of Massahusetts in Amherst. Casual contact with all of the academics mentioned above, and the rich history of physics and light that they passed on to me, made my time in academia most enlightening.

My 37-year career at GE, mostly in light source technology, brought me in contact with co-workers with backgrounds throughout the physical sciences, material sciences, engineering, and manufacturing specialties. The intellectual climate was very intense, and I learned things from every one of my co-workers. I am reluctant to start naming them for fear of overlooking someone. I was constantly impressed by how often the practical problems of the lighting industry crossed the many traditional disciplines of science and engineering. These practical problems even ventured into the unknown. It was great, at GE, to be in an environment where colleagues from these many disciplines supported one another, constantly teaching and learning. After GE, I have had a busy consulting business, almost entirely dealing with lighting. Throughout this period, which began with GE, I was mostly working on the technology of lighting products, but was also immersed in an environment that touched all aspects of light.

Electric lighting is only one of many modern applications of light, but it is the one that I know best. It provides an opportunity to highlight how the science learned in STEM courses comes into play in practical applications. Electric lighting also shows how science only goes so far, and that practical engineering techniques must come into play in refining actual products. Many other applications of light are mentioned, but not in significant depth.

I have encountered broader aspects of light along the way. Light plays a role in many biological processes, and I have chosen to emphasize human biological processes. Lighting also plays a significant role in architecture. Outside the world of STEM, light and color play a significant role in art, something I have come to appreciate more through my wife Karen and her sister Cynthia. Several aspects of this are included in the text.

Writing this book took around two years. The pieces were all in my head at the outset. However, the challenge was to fit them together in a way that tells a story. To this end, I quickly settled on a loosely chronological approach. I needed to do considerable fact checking through books and the Internet to fill in a few gaps, shore up areas where my memory was fuzzy, and develop the requisite references for the text. The target reader is a student who has taken some of the college physics curriculum, especially optics and modern physics, and wants to broaden their understanding of light. I recruited some student readers who were very helpful with suggestions for improving the organization and flow, as well as pointing out areas that required better explanation. Some seasoned professional colleagues were helpful in suggesting additional material and identifying a few areas that needed expansion.

My preferred publisher was AIP Publishing because they provide a direct route to my target reader. I was delighted when they showed interest around one year into the project. Their suggestions for improvement along the way always made sense, and I implemented them. In the end, the book is much more complete and polished than I could have imagined initially.