The discovery will make it possible to realize a new type of surface optical components on the nanometer scale based on the properties of the building blocks of the material which are the optical antennas (optical meta-atoms), and the symmetry properties - symmetry breaking of the photonic structure.
Technion researchers have developed a new type of photonic material, a Spin-Optical Metamaterial based on nanoantennas that enables the control of the radiative modes with the help of the spin of light. The discovery will make it possible to realize a new type of surface optical components on the nanometer scale based on the properties of the building blocks of the material which are the optical antennas (optical meta-atoms), and the symmetry properties - symmetry breaking of the photonic structure. With the help of planning the structure in which the antennas are arranged and their direction that changes in space, it is possible to control the interaction of light and matter and to design radiation modules.
The researchers published for the first time about the experimental discovery of the Optical Rashba effect, which makes it possible to add or subtract momentum to light by controlling the light's spin (degree of internal rotation of the photon - circular polarization) and the symmetry properties (symmetry breaking) of the structure. This groundbreaking research was carried out by researchers from Prof. Erez Hasman's group - Dr. Vladimir Kleiner and research students Nir Shtrit, Igor Yolwitz, Elhanan Magid, Dror Ozari, and Dekal Wechsler. According to Prof. Hasman from the Faculty of Mechanical Engineering at the Technion: "In the experiment, we created a structure in the form of a 'kagoma' (similar to the periodic structure of the Star of David) and showed the ability to control thermal radiant emission behavior with the help of spin-optical orbit interaction" as a result of breaking the structure's symmetry. The researchers called the scientific phenomenon the optical "Rashba" effect as an analogy to the Rashba effect of electrons in a solid state. The electronic Rashba effect allows controlling electrons with the help of the spin by breaking the symmetry of the structure. This effect is currently being used for the new field of "spintronics" which makes it possible to realize nanoelectronic components controlled by the spin of the electrons.
The inspiration for the research comes from the solid state: many studies have been done on antiferromagnetic materials in a kagome-shaped crystal structure. In these materials there is a physical phenomenon called Frustration: the magnetic moments can be arranged in different states (different phases) but the energy is degenerate. The Technion researchers noticed that there is a significant difference in the symmetry of the various states of the magnetic moments that go from a spatially symmetric crystal to a symmetry breaking one. It is known that the physical conservation laws are determined by the symmetry of the system. For example: circular symmetry requires conservation of angular momentum, and translational symmetry requires conservation of linear momentum. Likewise, when we have a physical system characterized by spatial symmetry breaking, we can expect dispersion splitting (explosion - the dependence of the light frequency on the momentum) as a spin dependence.
Instead of a different spatial arrangement of magnetic momets, the Technion researchers used a different arrangement of non-isotropic nanoantennas where the arrangement is the same as the different phases that exist in nature in antiferromagnetic materials in the Kagome structure. An optical nanoantenna makes it possible to create a local electromagnetic mode that depends on the geometry of the antenna. The researchers fabricated a metamaterial based on an array of SiC antennas and measured the thermal emission from the various structures. SiC is a material that supports phononic surface waves that are attached to the surface. Thermal excitation of the surface waves in a photonic structure allows them to be coupled to spatially and temporally coherent thermal radiation. The measurements show that by planning the symmetry breaking properties of the structure it is possible to control the directions of the electromagnetic radiation. The array of antennas emits or absorbs light when the phase between the antennas is determined by a geometric gradient that depends on the non-homogeneous and non-isotropic structure of the array. The researchers developed a theory that makes it possible to plan and control the radiative modes of the photonic structure with the help of the geometric phase as a result of a geometric gradient in the nanometer scale (Berry Phase) and obtained a match with the experimental results.
The researchers believe that the discovery will enable the development of a new type of optical components and nanophotonic devices that will enable the realization of optical logic gates controlled by the spin of the photons, components for optical computing, new spin-dependent light sources, ultra-thin surface lenses, the design of light fronts and laser beams in different wavelength ranges with the help of optics A surface with a structure on the nanometer scale, and control of thermal radiant emission. With the help of the new optical materials it is possible to plan the properties of emission, absorption, transmission, dispersion of the light, as well as the manipulation of surface waves for photonic chips. Following the promising discovery, Prof. Hasman expands his research group and intends to take in more excellent research students from different areas in order to continue developing the field of spin optics that has been developed in his group for the past thirteen years.
www.sciencemag.org
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The writer must connect the physical terminology to a more understandable ground, perhaps by explaining the utility of the discovery.
According to my understanding, there is a substance that is everywhere and in space and it is called a photon and waves of light and radiation pass through it, they managed to change the symmetry of the photon and thus control the wave of light or radiation
I agree. Also very technical. 🙂
In general, the structure received right circularly polarized light and as a result a stream of phonons was created in one direction,
And when it received left-polarized light, a stream of phonons was created in the other direction.
What's nice here is the fact that it can be taken beyond the direction of electric currents in general.
I guess it’s my ignorance….. But I didn’t understand anything 🙂
I didn't understand anything from the summary or the article either. The author seems to condescend to the readers, as if each of us has already completed a degree in materials engineering / electro-optics.
It is not clear how the editor of the website approved the article.
I have a feeling that none of the readers understood the content of the article, because there is too much technical terminology in the article that only researchers understand. It would have been desirable if the author of the article had used fewer and more understandable technical terms.
So a surface made of this material with the right control can display images?
Another step on the way to the maiden's cloak?