Engineering a Lighter Future: The World’s Largest Metalens Unveiled
In a groundbreaking development, a team of engineers has crafted the most substantial metalens to date, measuring an impressive 10 cm. This optical marvel is not only the largest of its kind but also surpasses traditional lenses with its slim profile and reduced weight. The creation of this metalens paves the way for its integration into commercial technology, particularly in areas where minimizing weight is crucial, such as satellite and drone technology.
The secret behind the metalens’ remarkable capabilities lies in the complex nanoscale patterns etched onto its surface. These patterns, designed with precision to match the wavelengths of visible light, enable the metalens to alter the speed of different light parts, effectively focusing light much like conventional lenses but with a significant reduction in weight.
The challenge of producing these intricate patterns on a large scale has been a significant hurdle until now. Joon-Suh Park, a physicist at Harvard University, reveals that they have mastered the mass production of these nanostructures. The Harvard group, led by Federico Capasso, has ingeniously adapted the metalens material to be compatible with semiconductor manufacturing equipment, which is traditionally used for creating nanoscale-patterned computer chips.
To achieve the desired lens size, the researchers divided their design into 25 segments and employed photolithography to pattern each segment onto a 200 mm glass wafer. This innovative stitching technique resulted in a 10 cm metalens adorned with 18.7 billion nanoscale pillars, each pillar standing approximately 1.5 µm tall and varying in diameter from 250 to 600 nm.
The metalens was tested in conjunction with a filter and an image sensor, demonstrating its ability to capture clear images of both nearby individuals and distant celestial bodies, including the moon and the sun. The focus was adjusted by altering the distance between the metalens and the sensor.
Anticipating the metalens’ potential use in aviation and space exploration, the researchers ensured its durability by subjecting it to extreme temperature fluctuations, from a chilling dip in liquid nitrogen at –200 °C to a scorching 200 °C hot plate, without sustaining any damage.
