Defining the classical and quantum limits of surface plasmon optics with hard-soft nanoantenna systems

Stanford University, Stanford CA

Investigators

Abstract

Title: Exploring the limits of optical enhancement with nanoscale antennas Non-technical description: Nanoscale antennas are a gateway to the next generation of miniaturized optical systems for communications, sensing, energy conversion, and optical imaging applications. The purpose of this research is to understand the physical limits of light manipulation with nanoscale metal antennas. In particular, our goal is to quantify these limits and to understand their connection with metal antenna geometry. We will probe the relationship between antenna geometry and optical properties by characterizing a metal antenna platform that can reconfigure as a function of mechanical strain. This research will help us develop new technologies, based on nanoscale optical devices, which can operate at their absolute physical limits. For example, it can be used to design ultra-sensitive sensing platforms with optical readout, which will serve as the cornerstone for new optically-based point-of-care biomedical technologies. It will also help us advance our understanding of green energy devices that utilize nanoscale antennas for photocatalytic and energy harvesting processes. Technical description: Optical antennas have tremendous potential in miniaturized photonic systems because they can tailor electromagnetic fields with unprecedented control. The research goal of this NSF proposal is to measure and quantify plasmonic near-field coupling and field-enhanced phenomena in the classical and quantum regime using devices that can dynamically reconfigure with extreme mechanical control. Three research objectives will be pursued to: i) understand how optical modes transform in mechanically-actuated antennas; ii) explore the non-linear optics of antennas with nanoscale gap spacings; and, iii) understand how symmetry breaking can control optical modes. To address these objectives, a new type of mechanically-tunable nanoantenna, consisting of plasmonic antennas mounted onto an elastomer, is proposed. The project outcome will fill a significant void in the field of quantum plasmonics and address significant fundamental questions that are scientifically unexplored, including: what are the fundamental field-enhancement limits in coupled antennas? How can the chemical surface modification of antennas impact their near-field coupling in the quantum plasmonics regime? How can device reconfiguration enable extreme sensitivity in optical sensors? By analyzing individual antennas with dynamically tunable configurations, as oppose to multiple devices with differing static configurations, uncertainties due to uncontrolled fabrication variations from device to device are eliminated.