Optical Science and Engineering doctoral student Shohreh Shadalou is one of five award winners in Synopsys’ 2020 Robert S. Hilbert Memorial Optical Design Competition.
The annual competition celebrates exceptional research projects designed using Synopsys’ optical software solutions. Shadalou competed against graduate and undergraduate students from across North America. Other winners are students from Rose-Hulman Institute of Technology, the University of Arizona, and the University of Rochester.
Shadalou’s project used freeform optics and Synopsys’ LightTools software to design a tunable LED-based desk lamp.
“Illumination engineering is the art of guiding the light from a given source to a desired target in an efficient manner,” Shadalou said. “Tunable illumination can improve functionality for different applications such as interior lighting, automotive lighting, medicine and dermatology, security cameras, and so on.” Other applications include virtual reality and augmented reality.
Fundamentally, optics are devices that control and direct light. Conventional optics such as lenses and mirrors are typically composed of flat, spherical or other symmetric shapes. Freeform optics contain more complex non-symmetrical shapes, and allow optical designers more degrees of freedom to improve the optical performance and reduce the size of optical systems.
The desk lamp project allowed for efficient tuning of the lamp’s light, from a small bright illuminated area to a larger illuminated area with a dimmer but uniform light. While the project had practical results, its deeper purpose was to serve as a conceptual example of the design process and its potential for other applications.
“The most interesting thing about this project is that it includes all three aspects of design, manufacturing, and testing of illumination systems,” Shadalou said. “Using the novel concept of freeform in following the idea and working towards realization as a final product was appealing to me. I became familiar with this field working with my mentor, Dr. Thomas Suleski, through a Center for Freeform Optics project.”
The Center for Freeform Optics, housed at UNC Charlotte and the University of Rochester, is focused on transforming the optics industry through freeform optics, with funding from the National Science Foundation and support from industry.
Shadalou and Suleski are collaborating with Dr. Matthew Davies and a student team in the Mechanical Engineering and Engineering Science Department to build a prototype of her design.
“I worked in industry for a number of years before becoming a professor,” Suleski said. “So it’s always in the back of my mind, with the research that we do, that while something might be a wild idea, it can be a wild idea with a payoff down the road. I really enjoy seeing projects like this come to fruition, something that hasn’t been done before and could be very useful.”
Industry collaborators with the Center for Freeform Optics also have shown excitement about the potential for the research, said Suleski, who is director of the UNC Charlotte CeFO site.
“I am so impressed by what Shohreh has done. This award is a big deal. Seeing our students perform and being recognized at this level is significant. The optics program at UNC Charlotte is relatively young in the field, and we’re performing at the level with programs that have been around much longer. We’re in that conversation now.”
— Dr. Thomas Suleski
Before pursuing her doctoral degree, Shadalou earned a master’s degree in mechanical engineering from UNC Charlotte. Here’s a bit more about the project, as described by Shadalou.
Q. Can you describe the underlying concepts involved?
Most of the time when people think about optics they are thinking of imaging. A camera system is a representative example. A lens (or group of lenses) is used to form and capture an image of an object on film or another sensor. High quality images will be precise, crisp, and clear, which drives very specific requirements on the shape and quality of the lenses or mirrors that are used.
Eyeglasses, contact lenses, microscopes and telescopes are other common examples of imaging optics and systems. For almost the entire over 1000-year history of imaging optics, such components have had radial symmetry around a central axis, largely because such surface shapes are easier to analyze, design, fabricate, and measure.
More recently, advances in computer aided design, computer numerically controlled manufacturing, and advances in measurement have enabled creation of freeform optics, which, simply put, are optical components that do not possess or require radial symmetry.
Relaxing the requirement for symmetry enables revolutionary improvements in imaging performance and order-of-magnitude reductions in system size, but places significant challenges and requirements on the accuracy of the freeform surface shapes themselves.
In contrast to imaging optics, illumination optics are intended to transfer light from a source to a target without the particular requirements or precision necessary for imaging. In many cases, an illumination system is intended to take a very non-uniform source of light and ‘transform’ it into a uniform light pattern with a particular shape or angular distribution.
Design procedures for illumination optics are complex and very different from standard processes for imaging optics. Optical components for illumination typically have looser tolerances on shape accuracy and smoothness than imaging optics, but can also have radically freeform shapes.
Simple examples include automotive headlights, television backlights, luminaires for room lighting, shaped mirrors for sunlight concentration in solar energy, and light-shaping elements for laser manufacturing.
Q. How have you prepared for this research project, and what have you learned from doing it?
My varied classes and experiences have prepared me for this design competition, which, in turn, has given me an opportunity to learn more about design and software tools.
I have taken optical theory and optical design courses as part of UNC Charlotte’s Ph.D. program in Optical Science and Engineering, which have helped me to have a better understanding of the governing rules of illumination and optical system design.
3D imagination and visualization skills from my mechanical engineering background accelerated the modeling process and helped me have a clearer vision of manufacturability of the design.
My programming skills also helped me in evaluating the system performance and analyzing the test results.
I thought I would gain a good documentation of the design process, even if I were not selected for the award. I also gained motivation, encouragement and confidence by receiving positive feedback about our design from experts. This competition was really good for me to give me the confidence that this was not just a simple idea. It’s a valuable design.
Words: Lynn Roberson with Shohreh Shadalou | Photo of Shadalou and Suleski: Lynn Roberson