Teaching Old Waves New Tricks: The Quest For Meta-Materials
For centuries we enjoyed light and sound as tools to manipulate, store and control the flow of information and energy. However, our need to transmit information and energy through these wave channels suffered a physical limit dictated by diffraction. For example, Young’s double slit experiments suggest that for an observer at a distance away from the two slits, one cannot distinguish these slits from one when the gap of these slits are close to wavelength of light. Can we overcome the diffraction limit by bending and folding waves, in a similar fashion to paper origami?
In this seminar, I will present our efforts to fabricate 3D complex microstructures at unprecedented dimensions. In the arena of sound waves, these structures show promise on focusing and rerouting ultrasound through broadband and highly transparent metamaterials. Recently our research effort on acoustic metamaterials has been expanded to tailoring the wavefront and energy flow of elastic waves. In the optical domain, we report our development of optical imaging probes to measure the distinct local modes in the nanostructures that promote electron-photon interaction down to layers of a few atoms thick, which promise for efficient light emission and detection. These novel metamaterials could be the foundation of broadband photo-absorbers, directional emitters, as well as compact and power-efficient devices.