An innovative breakthrough based on folding technology has enabled Chinese scientists to create the highest quality factor ring magnetic resonance metamaterial in the optical frequency band.
Ring magnetic pole moment - a mysterious electromagnetic phenomenon generated by a circular current or a magnetic dipole connected end-to-end, which has long been obscured by electrode and magnetic pole moments due to its weak intensity, making it difficult to directly observe like dark matter in the universe. It was not until 2010 that humans first captured its presence in the microwave band.
Now, a breakthrough research by the Institute of Physics of the Chinese Academy of Sciences has pushed ring magnetic resonance technology to a new height.
Microfolding Technique: Creating Impossible Electromagnetic Structures
Dr. Liu Zhe, Li Junjie and Gu Changzhi from the Micromachining Laboratory of the Institute of Physics, Chinese Academy of Sciences have developed a revolutionary micro nano processing technology - focused ion beam strain induced three-dimensional folding. The magic of this technology lies in:
Folding one-dimensional and two-dimensional materials in an orderly manner like "nanoorigami" multiple times
Realize precise 3D assembly of metal/dielectric composite structures
Free control of spatial configuration and geometric morphology at the sub micron scale
Researchers use transparent silicon nitride (SiNx) thin films as the skeleton to combine micro scale metal resonant rings at specific angles and positions in three-dimensional space, creating complex electromagnetic structures that traditional processes cannot achieve.
Record breaking quality factor of optical frequency band
When vertically incident light excites these metal resonant rings, a miracle occurs:
The metal resonant ring generates LC resonance, and the resonance modes of the resonant ring with different opening directions are coupled with each other. The magnetic dipole moment is connected at the beginning and end of the ring, forming a pure ring magnetic dipole resonance.
Through precise regulation, the team achieved a high quality factor of up to 6 in the mid infrared band for the ring magnetic resonance response, which is the highest value ever reported in the optical frequency band. Experimental data shows that at the resonance frequency, the ring magnetic dipole moment component (Tz) reaches its peak, confirming its dominant position.
Even more cleverly, when researchers used TM waves with a 75 ° oblique incidence, the radiation intensity of the ring magnetic dipole successfully surpassed that of the electric dipole and magnetic dipole, while maintaining excellent quality factors.
Application prospects: From precision sensing to plasmonic laser
The value of this breakthrough lies not only in its academic significance, but also in its broad application prospects:
Subwavelength Vortex Magnetic Field: Metamaterials can generate spatially localized vortex magnetic fields, providing new means for energy manipulation
Light field confinement ability: extraordinary electromagnetic energy localization ability and radiation suppression ability, significantly enhancing the interaction between light and matter
High sensitivity detection: The ultra-high Q-value characteristic greatly improves the detection limit of biochemical sensors
New type of laser: opening up a technological path for low threshold plasmonic lasers
This type of ring magnetic metamaterial based on surface plasmon induction will greatly facilitate the study of peculiar physical phenomena related to ring magnetic dipole moments, including ring dipole moment effects in optical, acoustic, biological, and chemical molecular systems, "the research team emphasized in the paper.
The Three Dimensional Path of Innovation in China
This study received joint support from the Ministry of Science and Technology of China (2016YFA0200803, etc.) and the National Natural Science Foundation of China (91323304, 11504414, etc.).
In 2017, the achievement was published as a cover article in the top materials science journal Advanced Materials, marking a significant breakthrough in China's field of three-dimensional metamaterials.
With the birth of high-quality factor ring magnetic metamaterials, Chinese scientists have opened a new door in fields such as infrared sensing, plasmonic lasers, and quantum energy conversion. This full chain innovation, from basic processing methods to physical mechanisms and application exploration, is rewriting the boundaries of human understanding of the electromagnetic world.
