Scientists propose new methods to accelerate the commercialization of superlens technology

Superlenses are nano artificial structures that can manipulate light, providing a technique that can significantly reduce the size and thickness of traditional optical components. This technology is particularly effective in the near infrared region, and has great prospects in various applications, such as LiDAR, which is called "the eye of autonomous vehicle", mini UAV and blood vessel detector.

Despite its potential, current technology requires tens of millions of Korean won to manufacture nail sized superlenses, which poses a challenge to commercialization. Fortunately, a recent breakthrough indicates that its production costs are expected to decrease by one thousandth in price.

A collaborative research team composed of Professor Junsuk Rho from the Department of Mechanical Engineering and the Department of Chemical Engineering at Pohang University of Science and Technology has proposed two innovative methods for large-scale production of superlenses and manufacturing them on large surfaces. Their research is published in the Review of Laser and Photonics.

Lithography is a process of manufacturing a superlens by printing patterns on a silicon wafer using light. Usually, the resolution of light is inversely proportional to its wavelength, which means that shorter wavelengths lead to higher resolution, allowing for the creation of finer and more detailed structures. In this study, the team chose deep ultraviolet lithography technology, which is a process that uses shorter wavelengths of ultraviolet light.
The research team recently achieved large-scale production of visible light region superlenses using deep ultraviolet lithography technology, which was published in the journal Nature Materials. However, due to the low efficiency of existing methods in the infrared region, challenges have arisen.

To address this limitation, the team developed a material with high refractive index and low infrared region loss. This material was integrated into the established large-scale production process, resulting in the successful manufacture of a relatively large infrared superlens with a diameter of 1 centimeter on an 8-inch wafer.

It is worth noting that this lens has an excellent numerical aperture of 0.53, highlighting its excellent light gathering ability and high resolution close to the diffraction limit. The cylindrical structure further ensures excellent performance without being affected by polarization, regardless of the direction of light vibration.

In the second method, the team employed nanoimprinting, a process that allows for the use of molds to print nanostructures. This process utilizes the knowledge of nanoimprinting technology accumulated through collaborative research with RIT.

This effort has been proven successful as the team managed to mass produce a 5-millimeter diameter superlens composed of approximately 100 million rectangular nanostructures on a 4-inch wafer. It is worth noting that this type of superlens exhibits impressive performance, with an aperture of 0.53. Its rectangular structure exhibits polarization dependence and can effectively respond to the direction of light vibration.

On the basis of this achievement, the team integrated a high-resolution imaging system to observe real samples such as onion skins, verifying the possibility of commercializing superlenses.

This study is of great significance as it overcomes the limitations of traditional individual production processes for superlenses. It not only helps to create optical devices with polarization dependence and independent characteristics, tailored for specific applications, but also reduces the production cost of superlenses by up to 1000 times.
Professor Junsuk Rho said, "We have achieved precise and rapid production of wafer level high-performance superlenses, reaching the centimeter level. Our goal is to accelerate the industrialization of superlenses and promote the advancement of efficient optical devices and optical technology through this research.".

Source: Laser Net