Free Form optical design B-Phot research is top downloaded at OSA (free access)
OSA is granting the optics and photonics community free access to a collection of the most downloaded articles in this topic area over the past year from Applied Optics . The article "Freeform optical design for a non-scanning corneal imaging system with a convexly curved image" resulting from the research of our VUB B-PHOT Postdoc Researcher Yunfeng Nie is among those most downloaded papers.
Techniques that are typically used by specialists to image the cornea are based on point, slit, or annular scanning due to a narrow field of view. The difficulty in achieving a larger field of view comes from the convex shape of the human eyeball.
Field curvature for a refractive imaging system with positive power is typically negative and thus a concave image surface. In order to view the full cornea and sclera with snapshot imaging, we calculate qualified two- and three-mirror solutions from Seidel aberration theory. A three-mirror solution is further optimized as a high-resolution off-axis imaging system using freeform surfaces, which can obtain a full-field tailored image shell without scanning. The lateral resolution on the cornea is about 10 μm with good modulation transfer function (MTF) and spot performance. To ease the assembly, a monolithic design is achieved with slightly lower resolution, leading to a potential mass production solution.
For more details, you can read the full article here