'Isotropic Shrinkage Of Patterned Vacancies Enables 3D Nanoprecise Metastructures For Visible Light Applications'

Fujikura Ltd. (Director, President and CEO: Naoki Okada) has been conducting joint research on "three-dimensional nanofabrication technology" with researchers from the Department of Mechanical Engineering, Biological Engineering, and the McGovern Institute at the Massachusetts Institute of Technology (MIT) in the United States. They have now published a co-authored paper, which has been released in the Nature Photonics series of scientific journals.

At Fujikura, the Advanced Research Core (ARC), established in 2019, conducts cutting-edge basic research, promoting state-of-the-art research in the fields of nanoscience and nanoengineering in collaboration with multiple MIT laboratories.

Highlights of Research Achievements in 3D Nanofabrication Technology
One nanometer (nm) is one millionth of a millimeter, and three-dimensional nanofabrication technology refers to techniques for forming nanoscale structures and shapes with a high degree of freedom in three dimensions. Among nanometer-scale fabrication methods, lithography—widely used in the production of semiconductors and integrated circuits—is a representative approach. However, such methods are specialized in forming planar structures and therefore offer limited design freedom for creating complex three-dimensional structures.

The newly reported method, ImpCarv*1, is a photofabrication technique that constructs complex three-dimensional structures by scanning and exposing light in motion. It achieves a resolution far beyond the conventional “diffraction limit of light,” which has long been considered a fundamental challenge for photofabrication methods.

Photofabrication: Potential and Future Applications in Next-Generation Technologies
The photofabrication method, in which structures are formed by scanning and exposing light in motion, has the unique advantage of enabling the free fabrication of multiple structures even within a small plastic substrate of about 1 mm².

This makes it possible to create complex functional devices in which numerous functional elements are fabricated within a single substrate. Since these elements can be fabricated simultaneously, there is no need to precisely align and position them one by one, thereby improving production efficiency.

Moreover, the nanoscale microstructures produced by this method excel at precisely controlling various physical phenomena that occur at the nanoscale, making the technology broadly applicable across many fields. In particular, in the field of photonics, the ability to finely and flexibly control the shape, intensity, and phase of light opens the door to innovative photonic devices and components for optical communications and beyond. In this study, a demonstration of an optical neural network*2 fabricated using the unique features of ImpCarv was also conducted. In a proof-of-concept experiment*3 using the four digits “1, 5, 6, and 7,” it was demonstrated that the optical neural network could classify numbers in a manner similar to artificial intelligence (AI).

This optical neural network is expected to have applications not only in optical communications, but also in optical computing—where light, rather than electrons, is used to perform high-speed calculations—and in next-generation robotics.

Fujikura will continue to promote research in the field of nano-innovation, contributing to both customer value creation and the resolution of social challenges.