Researchers have engineered a spiral-shaped lens capable of sustaining clear focus across different distances and under changing light conditions. Like progressive lenses utilized for vision correction, this innovative lens eliminates the distortions commonly associated with traditional alternatives. Its potential applications span a wide range, from enhancing contact lens technologies to refining intraocular implants for cataracts and miniaturized imaging systems.
Researchers have developed a new type of lens that uses a spiral-shaped surface to maintain a clear focus at different distances in varying light conditions. Image Credit: Laurent Galinier
Unlike existing multifocal lenses, our lens performs well under a wide range of light conditions and maintains multifocality regardless of the size of the pupil, and for potential implant users or people with age-related farsightedness, it could provide consistently clear vision, potentially revolutionizing ophthalmology.
Bertrand Simon, Photonics, Numerical and Nanosciences Laboratory (LP2N)
LP2N is a joint research unit between the Institut d'Optique Graduate School, the University of Bordeaux, and the CNRS in France.
The researchers disclosed the new lens, which they term the spiral diopter, in Optica, published by Optica Publishing Group. Its spiraling elements, akin to having several lenses in one, are organized to create numerous distinct places of focus. This allows for clear vision at different distances.
In addition to ophthalmology applications, the simple design of this lens could greatly benefit compact imaging systems, and it would streamline the design and function of these systems while also offering a way to accomplish imaging at various depths without additional optical elements. These capabilities, coupled with the lens's multifocal properties, offer a powerful tool for depth perception in advanced imaging applications.
Bertrand Simon, Photonics, Numerical and Nanosciences Laboratory (LP2N)
Creating a Vortex of Light
The spiral lens design was conceived when Laurent Galinier, the first author of the study and a representative of SPIRAL SAS in France, examined the optical characteristics of individuals with significant corneal deformations. This inspired him to create a lens that spins light like water down a drain, thanks to its unusual spiral form.
The lens may provide clear focus at various distances because of this phenomenon, which is called an optical vortex and produces numerous distinct focus points.
Creating an optical vortex usually requires multiple optical components, and our lens, however, incorporates the elements necessary to make an optical vortex directly into its surface. Creating optical vortices is a thriving field of research, but our method simplifies the process, marking a significant advancement in the field of optics.
Laurent Galinier, Study Author, SPIRAL SAS
The scientists devised the lens by using advanced digital machining to mold the unique spiral design with high precision. They then validated the lens by using it to image a digital ‘E,’ much like those used on an optometrist's light-up board.
The researchers noted consistent image quality irrespective of the aperture size employed. Additionally, they uncovered that the optical vortices could be manipulated by adjusting the topological charge, essentially representing the number of windings around the optical axis. Volunteers who utilized the lenses also reported significant enhancements in visual acuity across a spectrum of distances and lighting conditions.
Crossing Disciplines
The development of the new lens demanded a fusion of the meticulously crafted design with cutting-edge fabrication techniques achieved through interdisciplinary collaboration.
Simon said, “The spiral diopter lens, first conceived by an intuitive inventor, was scientifically substantiated through an intensive research collaboration with optical scientists, and the result was an innovative approach to creating advanced lenses.”
Currently, the researchers are trying to learn more about the distinctive optical vortices that their lens produces. They also intend to conduct systematic trials to determine the lens's efficacy and benefits in real-world scenarios, including its capacity to correct people's vision. Furthermore, they are investigating the possible use of this approach to prescription eyeglasses, which may provide users with clear vision at various distances.
Simon concluded, “This new lens could significantly improve people’s depth of vision under changing lighting conditions, and future developments with this technology might also lead to advancements in compact imaging technologies, wearable devices, and remote sensing systems for drones or self-driving cars, which could make them more reliable and efficient.”
Journal Reference:
Galinier, L., et.al., (2024). Spiral Diopter: Freeform Lenses with Enhanced Multifocal Behavior. Optica. doi.org/10.1364/OPTICA.507066