Tandon Grad Doesn’t Just Know Optics, She Co-Wrote the Book

A physics student walks into an optics class ... and writes the textbook. That’s no joke. In 2016 Kaitlynn Snyder, then a junior at NYU Tandon majoring in applied physics, decided to audit an optics course for engineering majors taught by University Professor Stephen Arnold and wound up with top billing for Introduction to Modern Optics for Students in Engineering and Applied Science. The text was based upon Arnold’s four-hour-per-week spring semester course PH 3474 (and EE 3474). Snyder immersed herself in the subject matter — and in learning a pedagogical approach to translating the material for students, a bit of historical background, and even some quirky formatting challenges, such as which software to use to make mathematical formulas display correctly. 

It was good timing. Renowned for such innovations as the Whispering Gallery Mode (WGM) biosensor — an exquisitely sensitive microfluidic biochip that can sense the presence of even a single virus-sized particle — Arnold was facing a non-scientific challenge in 2016: how to help students across the bridge from fundamental classical physics (essentially physics through the late 1800s up to Maxwell’s electrodynamics) to the more advanced math and physics required for optics, including the rudiments of relativity and quantum mechanics. 

No such text quite fit the bill since existing ones were a bad combination of too advanced and too expensive, especially if the book had to be shoe-horned into a course for which it was not quite designed. 

“For a while, I was using a traditional text,” said Arnold, “But the level was just too advanced, so I decided I needed a book that could transition them from the courses they had already taken.” 

Fortunately, as Thomas Potts Professor of Physics, Arnold had access to a small discretionary budget giving him the wherewithal to hire Snyder as a paid intern. 

Arnold said Snyder, who also served as class assistant, organized the text from her notes of his lectures and from his slides; created the graphics for each chapter — a task that involved crafting some 20 pages of highly organized content after every one of the 25 optics classes; and uploaded it to students the same evening. 

“This required her to spend as many as four hours each class day, modifying her notes and sometimes doing historical research to add context to a reference I may have made. It was a tremendous amount of work,” he said. 

Arnold and Snyder’s course begins where the introductory physics sequence ends — Maxwell’s four equations. But instead of a purely theoretical discussion, they introduced such diverse topics as optical tweezers, holographic diffraction grating, Polaroid co-founder Edwin Land and the motivation for polarized spectacles, the demystification of the structure of DNA from Rosalind Franklin’s X-ray diffraction image, super high-resolution microscopy, Arnold’s own WGM devices, the human eye, and much more. 

Snyder did the legwork to add context to these discussions in the book. “As class assistant, obviously she had to review what was covered in each class, adding other content afterward, including personal narratives to illustrate the science,” said Arnold. “She even took the exams!”

Snyder explained that framing a theoretical and experimental description of applied science and math with historical context made the experience richer and less hypothetical.

“There are places where I found myself interested in how different experiments were actually done, and when and how certain technologies arose,” she recalled. “I liked doing the background research for these and doing reading on my own; I even did a short presentation on Rosalind Franklin in class.” 

She said that the course particularly appealed to her because of its focus on experimental examples: “I really liked that it explored so many real applications. I found that fascinating because in a lot of courses you end up learning mathematical formalism without knowing as much about experiments or actual applications.”

She said the experience of helping to shape the course, rather than just listen to it, was invaluable, turning an otherwise passive “lean back” experience into an active one. “I think I learned a lot more than I would have otherwise,” she said. “It’s one thing to see and hear the material in the class, but then trying to explain it gave me a whole new breadth of understanding.” 

Having an enthusiastic collaborator in Snyder was serendipitous because, as Arnold explained, she both understood the science and was a good writer. “She has the ability to assimilate material, to turn it into words. Her ability to write is frankly rare in engineering,” he said. 

Also, besides having the math and science to understand all of it, Kaitlynn is really interested in the historical context. So when I brought up experiments and technologies of historical significance, she did the background reading, and did a great job of making it part of the book.”

Once the book was completed this year, Arnold decided to eschew the traditional academic publishing house route and instead self-published it as a custom, printed-on-demand Amazon full-color text that students can order for just $40 — over $100 less than a comparable text on optics. 

Snyder, now a doctoral student in physics at the NYU College of Arts and Science, received a Henry M. MacCracken Program Fellowship, including full scholarship, to pursue her degree, thanks in part to her contributions to Introduction to Modern Optics. “Besides everything it taught me, doing this book really helped me get into the program,” she said.

She and Arnold are now co-writing a follow-up on bio-optics for engineers, based on the text of a new fall class, Bio-Optics (BE 6303), offered by Tandon’s newly formed Biomedical Engineering Department. The book delves into applications such as Arnold’s own work on WGM microfluidic devices, scanning microscopy, optical tweezers used to manipulate cells, the role fundamental optics played in the discovery of the structure of DNA, Lasik eye surgery, Young’s interferometric virus sensor, and more.