William J Cassarly

William J. Cassarly, a life-long learner, innovator, and lecturer in non-imaging optics, optical design, and optical software development, is currently an Optical Scientist at Keysight Technologies. Cassarly earned his BSEE from Bucknell University and his PhD in electrical engineering from the University of Pennsylvania. He launched his career in non-imaging optics at General Electric, moving through roles in its Aerospace, Corporate R&D, and Lighting Divisions. Prior to joining Keysight Technologies, he drove algorithm development for optical software products at Optical Research Associates (ORA), which was acquired by Synopsys.

Throughout his career, Cassarly has been recognized for his efforts to create the field of computer-aided illumination engineering that spans illumination free-form design and illumination optimization. He has shared his passion and expertise for this subject through numerous papers and invited talks, educational courses, intellectual property development, and illumination engineering consulting.

His role as an optics innovator is evidenced in his 50+ US patents and well over 100 publications and conference proceedings, including book chapters in recognized references such as the Handbook of Optics. His notable technical work includes designing the TIROS lens for LED flashlights and providing key contributions to major feature developments in LightTools® and LucidShape®, such as Freeform Designer, Measured BSDF, Backlight Pattern Optimization, and the first industry introduction of a practical and effective optimization environment for illumination systems. His most recent achievements encompass the core stray light features in ImSym, which was the Laser Focus World Platinum Level Winner of the 2025 Annual Innovators Award Program.

He is a Fellow of SPIE, a member of Optica, and a recipient of the David Richardson Medal.