Lets say a hypothetical state of affairs the place two people are gripping a rope, every holding one finish. Individual A proceeds to shake the rope in an up-and-down movement, thus producing a propagating wave that travels in the direction of individual B. Now, if individual C, positioned between individual A and B, engages in a comparable frequency of waving movement as that of the rope’s wave, might the wave be redirected again to individual A fairly than reaching individual B? Initially, this example seems implausible, as individual C doesn’t bodily work together with the rope held by individual A and B, seemingly defying the opportunity of reaching a 100% wave reflection just like that noticed in an ideal mirror. Nonetheless, this phenomenon finds clarification throughout the area of physics and is named the “certain state within the continuum (BIC).”
The research of BIC has encompassed numerous disciplines together with quantum mechanics, optics, semi-conductors, and nano-optics. Using this phenomenon facilitates the confinement of sunshine particles, or photons, stopping their ahead propagation. Furthermore, BIC holds promise for the event of extremely delicate sensors. Earlier analysis into BIC has predominantly centered on microscale and nanoscale contexts whereas investigations utilizing seen buildings to clarify this phenomenon have been absent.
Lately, a analysis crew led by Professor Junsuk Rho from the Division of Mechanical Engineering and the Division of Chemical Engineering and PhD candidates Dongwoo Lee, Jeonghoon Park, and Seokwoo Kim from the Division of Mechanical Engineering at Pohang College of Science and Expertise (POSTECH) efficiently demonstrated certain states within the continuum by way of the utilization of an acoustoelastic coupling construction for the primary time. The analysis findings have been revealed in Excessive Mechanics Letters, one of many world’s most influential journals within the discipline of mechanics.
The analysis crew designed an experiment setup aimed toward verifying the existence of the BIC phenomenon by way of the interaction of sound and elasticity. Commencing with the fabrication of an elastic bar resembling a stick, the crew proceeded to induce vibrations within the elastic bar by way of a shaker. Subsequently, air injection at a predetermined location on the elastic bar engendered coupling between sound and elasticity.
Within the experiment, when the frequency of the elastic progressive wave aligned intently with the resonance frequency generated throughout the acoustic cavity, a robust interplay manifested, ensuing within the full reflection of the progressive elastic wave. In essence, the elastic wave reverted again alongside the course it got here from, changing into indefinitely confined inside a sure house, just like the habits noticed when encountering a mirror, regardless of having ample room for ahead propagation. Whereas many research have explored the utilization of certain states within the continuum, this analysis represents the primary occasion of unveiling the BIC phenomenon by way of the mix of elasticity and sound.
Professor Junsuk Rho emphasised the potential implications of the findings, “This research illustrates that functions of acoustoelastic coupling will be expanded to vibration focusing and power storage.” He added, “The findings from this analysis maintain promise for numerous functions together with the event of filters able to selectively isolating particular frequencies or the development of power harvesting methodologies that convert kinetic power into electrical power.”
The research was carried out with the assist from the Ministry of Science and ICT and the Nationwide Analysis Basis of Korea.