IT IT Metalens Technology Is Advanced by Samsung and POSTECH Through a Study in Nature Communications -

The highly regarded academic journal Nature Communications has published a research paper titled “Compact eye camera with two-thirdss wavelength phase-delay metalens.” The study, which was carried out as part of a collaborative industry-academia project between Samsung Electronics and Pohang University of Science and Technology (POSTECH), focuses on ultra-compact metalenses for eye cameras.

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Professor Junsuk Rho of POSTECH and Dr. Jeong-Geun Yun of Samsung Research co-led the study. The co-first author was POSTECH researcher Hyunjung Kang. Samsung demonstrated the promise of next-generation photonic device technologies and new prospects for product differentiation by using a holistic strategy that included conception, execution, and validation.

The innovation holds promise for lowering the height of smartphone camera modules and decreasing the thickness and weight of extended reality (XR) devices. This might potentially address the issue of the “camera bump,” which occurs when the camera protrudes from the device’s body. Most significantly, the group was able to overcome long-standing technological obstacles that had prevented metalenses from being commercialized.

Instead of depending on curved surfaces like conventional lenses, a metalens is an ultra-thin lens that manipulates light using nanostructures placed on a flat surface. These nanostructures are far thinner than a human hair. Metalenses are perfect for creating small, light optical devices because of their shape.

One wavelength, or the distance light travels in a single oscillation, must be phase delayed¹ in order for a metalens to properly control light. A crisp picture is produced by this phase delay, which makes sure that light waves overlap correctly at the focal point. It has usually taken tens of millions of incredibly tall and thin nanostructures with aspect ratiosof at least 1:10 to accomplish this. These structures provide a significant obstacle to commercialization since they are hard to produce and prone to breaking.

Instead of utilizing the traditional full wavelength phase delay, the team was the first in the world to suggest a way to achieve light diffraction using only two-thirds of a wavelength. This method takes use of the fact that, even when there is a two-thirds wavelength phase delay, the nanostructures that make up a supercell³ maintain a steady phase gradient, which keeps the wavefront steady in the far field.

This technique made it possible to lower the aspect ratio to around 1:5, as phase delay is proportional to the width and height of a nanostructure. Consequently, the height of the nanostructure was reduced without affecting optical performance. These enhancements increase production and cost competitiveness, improve structural stability, and lower fabrication complexity and failure rates.

The researchers created an incredibly small infrared eye camera for XR gadgets using the recently created metalens. The camera showed precise pupil tracking and iris pattern identification despite its tiny profile.

The team decreased the camera’s thickness from 2.0 millimeters to 1.6 millimeters by incorporating the metalens, which resulted in a 20% reduction in weight and volume when compared to traditional refractive-lens cameras. At a broad 120-degree field of vision, the device also accomplished accurate gaze tracking and iris feature-point detection. Furthermore, the performance of the modulation transfer function (MTF)⁴ increased from 50% to 72%.

In order to manage light diffraction, this work presents a novel design strategy that lowers the need for phase delays while maximizing optical performance, mechanical stability, and cost-effectiveness.

In the future, it is anticipated that the technology will extend into the visible light spectrum and be used to reduce the protrusion of smartphones’ cameras and shrink a variety of image sensor systems, opening the door for new kinds of device differentiation.

In order to acquire next-generation technologies that contribute to the shaping of the future, Samsung will persist in pursuing a variety of research activities, including industry-academia cooperation.