Article: published in Nature Communications by Francisco J. Garcia-Vidal, IFIMAC researcher.
Nano-scale manipulation of light is an important topic in Nanophotonics. Many nanoscale structures are used to control the polarization, intensity, phase and wavelength of light. However, both the difficulty in designing high-capacity photonic devices with extremely rich nanostructures, and the lack of reliable numerical methods for their modeling severely refrain the development of real-world nanophotonic devices. We know that if we had a powerful numerical tool to design devices possessing a large number of fine/rich nanoscale features, we would be able to reach a new flatland with unprecedented opportunities.
Thanks to a joint theory/experiment collaborative project between the director of IFIMAC, Prof. Francisco J. Garcia-Vidal, and two experimental groups based in Singapore, an important leap forward into this direction has been recently achieved. These researchers have been able to design and test two types of nanosieves, both composed of thousands of nanoholes, devised to realize two different functionalities: i) a high-quality hologram and ii) a sub-diffraction spot in the far field. The nanosieve hologram is composed of 34034 nanoholes that are randomly distributed and whose sizes are tuned. The device shows good uniformity, high diffraction efficiency and its performance is polarization-independent. Also, as a difference with previous approaches, it does not produce twin images, which could lead to benefits across fundamental physics research and industrial applications. Using a completely different design, these researchers have also devised a nanosieve that is able to generate a sub-diffraction-limit focusing spot of size 0.32 λ well below the diffraction limit, emerging in the far field and in air ambient conditions. This new nanosieve will have profound implications in the research field of high-resolution imaging and focusing. [Full article]