Title: Plasmonic Surface Lattice Resonances: Theory and Computation

Abstract

In overview, plasmonic surface lattice resonances (Plasmonic SLRs) are mixed light-matter states emergent in a system of periodically arranged metallic nanoparticles (NPs) under the constraint that the array spacing is approximately equal to an integer multiple of the wavelength of optical frequency light divided by the index of refraction of the surrounding medium. The properties of SLRs derive from two separate physical effects; the electromagnetic (plasmonic) response of metal NPs, and the electromagnetic states (photonic cavity modes) associated with the array of NPs. Metal NPs, especially free electron metals such as silver, gold, aluminum and alkali metals, support optical-frequency electron density oscillations known as localized surface plasmons (LSPs). The high density of conduction-band electrons for these metals gives rise to plasmon excitations that strongly couple to light even for particles that are several orders of magnitude smaller than the wavelength of the excitation source. In this sense, LSPs have the remarkable ability to squeeze far-field light into intensely-localized near-electric-fields that can enhance the intensity of light by factors of ~ 10³ or more. Moreover, due to advances in the synthesis and fabrication of NPs, the intrinsic dependence of LSPs on NP geometry, composition, and size can readily be exploited tomore » design NPs with a wide range of optical properties. One drawback in using LSPs to enhance optical, electronic, or chemical processes is the losses introduced into the system by via dephasing and Ohmic damping - an effect which must either be tolerated or mitigated. Plasmonic SLRs enable the mitigation of loss effects through the coupling of LSPs to diffractive states that arise from arrays satisfying Bragg scattering conditions, also known as Rayleigh anomalies (RAs). Bragg modes are well known for arrays of dielectric NPs, where they funnel and trap incoming light into the plane of the lattice, defining a photonic cavity. The low losses and narrow linewidths associated with dielectric NPs produce Bragg modes that oscillate for ~ 10³ - 10⁴ cycles before decaying. These modes are of great interest to the meta-materials community but have relatively weak electric fields associated with dielectric NPs, and therefore are not used for applications where local field enhancements are needed. Plasmonic lattices, i.e., photonic crystals composed of metallic NPs, combine the characteristics from both LSPs and diffractive states, enabling both enhanced local fields and narrow linewidth excitations, in many respects providing the best advantages of both materials. Thus, by controlling the periodicity and global symmetry of the lattice, in addition to the material composition and shape of the constituent NPs, SLRs can be designed to simultaneously survive for up to 10³ cycles while maintaining the electric field enhancements near the NP surface that have made the use of LSPs ubiquitous in nanoscience. Modern fabrication methods allow for cm²-scale patches of two-dimensional (2D) arrays that are composed of approximately one trillion NPs, making them effectively infinite at the nanoscale. Because of these advances, it is now possible to experimentally realize SLRs with properties that approach those predicted by idealized theoretical models. In this Account, we introduce the fundamental theory of both SLRs and SLR-mediated lasing, where the latter is one of the most important applications of plasmonic SLRs that has emerged to date. The focus of this article is on theoretical concepts for describing plasmonic SLRs and computational methods used for their study, but throughout we emphasize physical insights provided by the theory that aid in making applications.« less

Authors:

Cherqui, Charles  ^[1];

• Search DOE PAGES for author "Cherqui, Charles"
• Search DOE PAGES for ORCID "0000-0003-2818-7973"

Bourgeois, Marc R.  ^[1];

• Search DOE PAGES for author "Bourgeois, Marc R."
• Search DOE PAGES for ORCID "0000-0002-9435-9051"

Wang, Danqing  ^[1];

• Search DOE PAGES for author "Wang, Danqing"
• Search DOE PAGES for ORCID "0000-0002-7369-1944"

Schatz, George C.  ^[1]

• Search DOE PAGES for author "Schatz, George C."
• Search DOE PAGES for ORCID "0000-0001-5837-4740"

---

+ Show Author Affiliations

1. Northwestern Univ., Evanston, IL (United States)

Publication Date:

Thu Aug 29 00:00:00 EDT 2019

Research Org.:

Northwestern Univ., Evanston, IL (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences, and Biosciences Division; National Science Federation (NSF)

OSTI Identifier:

1594602

Grant/Contract Number:  

SC0004752; DMR-1608258

Resource Type:

Accepted Manuscript

Journal Name:

Accounts of Chemical Research

Additional Journal Information:

Journal Volume: 52; Journal Issue: 9; Journal ID: ISSN 0001-4842

Publisher:

American Chemical Society

Country of Publication:

United States

Language:

English

Subject:

77 NANOSCIENCE AND NANOTECHNOLOGY; plasmon; surface lattice resonance; metal nanoparticle