Photonics Rules of Thumb Celebrates Third Edition and Three Decades of Optics Insights

"Sensing is applied science. Science is a set of rules. Therefore, we have prepared this little paper to convey some rules that may help you understand what sensor people are talking about and to explain some of the terms they use."

With that introduction, the seminal "Dr. Photon's Rules of the Ether" was born. That initial version — a two-and-a-half-page manifesto which covered nearly 30 rules including topics such as the Planck function, Rayleigh criteria and detection criteria — was drafted in 1991 by SPIE Fellow John Lester Miller and Ed Friedman and has had an impressively exponential trajectory. This month, nearly three decades later, SPIE Press will publish the third edition of Photonics Rules of Thumb: Optics, Electro-Optics, Fiber Optics, and Lasers. The latest version clocks in at over 700 pages, boasts five authors, and covers more than 400 rules.

Miller and Friedman met in Denver in 1985. They were both working for a major government contractor on what were then exotic electro-optical systems. "Those were halcyon days, with contract money flowing like water for concepts that were overly optimistic or barely possible at best," they recall in their new introduction. "In the center of the whole fray were bureaucrats, politicians, and managers who were demanding that we design systems that would be capable of the impossible. We saw many requirements being levied on our systems that were far from realistic, often resulting from confusing (and poorly understood) interpretations of the capabilities of optical and electro-optical systems and the properties of targets or backgrounds."

In 1991, they decided to try to educate everyone by creating "a half-serious, half-humorous posting for the local online bulletin board (this was before websites were ubiquitous)" which rapidly became known as "Dr. Photon's Rules of Thumb." Its content was a list of basic rules that apply when optics or electro-optics are being used. "We made the point that only a few miracles are allowed in a single design," they note today. "This short ‘white paper' found its way into the contractor community with which we worked, and we realized there was room for a fully fledged book." The first volume of Rules of Thumb was published in 1996; to keep pace with the dramatic maturation of the photonics industry, a second edition followed in 2004.

A decade and a half later, that industry has seen even more changes. As a direct consequence, the latest edition provides a widely updated selection of topics — including astro-photonics, autonomous vehicle technology, degraded visual environments, and focal plane arrays — and three more field experts as authors: SPIE Fellow Jack Sanders-Reed, who, in the past four decades, has worked the areas of medical imaging, surface science, and pilot vision systems and atmospheric phenomenology, as well as target detection, tracking, and photogrammetry, covering the electro-magnetic spectrum from hard X-ray through visible and infrared to millimeter wave with both passive and active imaging; Katie Schwertz, an optical and optomechanical designer who primarily works on commercial and industrial optical subsystems; and Brian McComas, a former PhD student of Friedman's with more than 30 years' experience working on electro-optical systems for military, astronomical, remote sensing, and industrial use.

Today, as the book's authors note, photonics is ubiquitous in everyday life, integral to commercial, military, medical, telecommunications, industrial, and automotive applications. In the 1970s, lasers and solid-state detectors were expensive and had only science and military applications; by the 1990s, their application expanded into the medical, industrial, and telecom arenas, and most consumers owned several lasers in their CD players and laser printers. At the turn of the 21st Century, charge-coupled device and complementary metal-oxide-semiconductor cameras were expanding beyond the realms of scientific instruments and advanced military usage: at that time, a three-megapixel camera was pretty advanced. Now everyone has a camera in their phone. Twenty years ago, we all had a few cathode-ray tube TV and computer displays; today, flat screens of much higher performance and much lower cost appear in myriad products ranging from car dashboards to refrigerators.

And photonics continues to develop and expand. We see ever-escalating levels of interest and investment in autonomous vehicle technology ("Single vehicle autonomy is easy: don't hit anything!" notes Sanders-Reed. "The hard part is sensing and understanding the continuously evolving environment, using sensors to build a dynamically evolving world model.") There are perpetually new advancements in infrared imaging, and cutting-edge improvements in optical design manufacturing. As the field continues to open new markets and contribute new applications, the manipulation and control of light is now critical to the very functioning of our society. The future is bright (pun intended) for our industry, holding promise for as yet unimagined possibilities, opportunities, and benefits to humanity.

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