EAGER: Ultra-High Frequency Phononic Devices

University Of Maryland, College Park, College Park MD

Investigators

Abstract

Surface acoustic wave propagation through engineered "phononic" crystal lattices was shown by theoretical and experimental evaluations to result in exciting new properties with "pass" and "stop" frequency bands, fractional wavelength propagation, mode hopping and high frequency resonances. The theoretical and experimental research on the propagation of surface acoustic waves through these lattices can be controlled by the size and geometry of the unit cell of these engineered structures. Yet, most of the work has been limited to moderate frequencies at megahertz ranges. Fundamentally, these structures can reach ultra-high frequency ranges through scaling down and design. This EAGER project proposes to study the problem of increasing the frequency of operation to ultra-high frequencies of such surface acoustic wave structures by developing a novel nanostructured phononic lattice device and exploring its properties. Furthermore, a novel fully integrated surface acoustic wave-phononic lattice device is proposed that has the potential to provide unique acoustic wave logic functions. The potential benefits of this research can be transformational in the electronics industry as a new family of acoustic wave devices can be developed with unique properties in the ultra-high frequency, and digital switching domain, with a host of key applications, such as superlensing imaging at fractional wavelengths, ultra-high frequency acoustic resonance filters for secure communications, switching phononic logic elements, ultra-sensitive sensing and others. The fundamental understanding of these structures will advance substantially the field of acoustic wave propagation and generation and will allow incorporation of such research in most electronics text books that will benefit student development. In societal needs it is anticipated to have a tremendous impact through applications in ultra-high frequency secure communications, acoustic logic elements, superlensing acoustic imaging for airport security, ultra-high sensitivity sensors, that are critical to societal needs for home, hospitals, institutions, airports, schools and vehicle safety. The goal of the project is to explore and develop a novel family of ultra-high frequency acoustic nanodevices based on phononic lattices of self-assembeled nanostructured thin films with different unit cell size and geometry. Three key innovative approaches will be introduced and employed for this project (a) the development of the self-assembly of piezoelectric nanostructures for the phononic lattice with the study of its fundamental acoustic wave properties, (b) the development and study of the surface acoustic wave inputs and outputs for the nanostructured phononic lattice, and (c) the integration of the nano-phononic lattice with inputs and outputs for an active acoustic wave logic element. The project will design for fundamental frequencies f0 in the gigahertz range and and study upconversion through fractional wavelength and scaling-down to sub-terahertz ranges. The proposed novel approach to developing a new family of acoustic nanodevices will explore the properties of the nano-phononic lattices theoretically and experimentally, explore frequency upconversion, mode hopping to higher frequency optical branches, and higher order resonances through the phononic lattice for ultra-high frequency applications.The proposed research focuses on introducing and exploring new concepts in phononic device development for ultra high frequency performance and unique capabilities for active switching that has a potentially transformative impact on integrated acoustic devices and circuits.