Plexcitonic strong coupling: unique features, applications, and challenges

Abstract

There are, recently, remarkable achievements in turning light-matter interactions into strong coupling quantum regime. In particular, room temperature plexcitonic strong coupling in plasmon-exciton hybrid systems can bring promising benefits for fundamental and applied physics. Herein we will review theoretical insights and recent experimental achievements in plexcitonic strong coupling and divide this review into two main parts. The first part will briefly introduce the general field of strong coupling, including its origin and history, physical mechanisms and theoretical models, as well as recent advanced applications of strong coupling, such as the quantum or biochemical devices enabled by optical strong coupling. The second part will zoom in and concentrate on plexcitonic strong coupling by introducing its unique features and new potentials (such as single-particle ultrastrong coupling, strong coupling dynamics in femtosecond scale) and discussing the limitations and challenges of plexcitonic strong coupling, which will also be accompanied by potential solutions such as the microcavity-engineered plexcitonics, spectral hold burning effects, and metamaterial-based strong coupling. Finally, we will summarize and conclude this review, highlighting the future research directions and promising applications.

Strong coupling between longitudinal and U-shaped localized surface plasmon modes in rectangular grating-shaped gold nanostructures

“…Recently, in a structure composed of Au antennas embedded in middle of two planar Au mirrors filled with SiOx, the strong coupling between Au mirrors Fabry–Perot photon modes and Au antennas LSPR mode has been experimentally demonstrated 19 . Similar LSPR-participated strong coupling phenomena are also observable in many other experimental systems 22 . Although the LSPR modes coupled with quantum emitters, SPP mode, and cavity photon mode have been intensively investigated, and the LSPR-LSPR coupling is also reported in nanoparticles array structures, 20 , 21 so far the strong coupling between different LSPR modes inside the individual metallic nanoparticle (nanostructure) is still rarely investigated, 23 and one reason is that it might be challenging to recognize the original uncoupled LSPR modes and adjust their resonance frequencies (wavelengths) separately through adjusting the individual particle geometry.…”

“…19 Similar LSPR-participated strong coupling phenomena are also observable in many other experimental systems. 22 Although the LSPR modes coupled with quantum emitters, SPP mode, and cavity photon mode have been intensively investigated, and the LSPR-LSPR coupling is also reported in nanoparticles array structures, 20,21 so far the strong coupling between different LSPR modes inside the individual metallic nanoparticle (nanostructure) is still rarely investigated, 23 and one reason is that it might be challenging to recognize the original uncoupled LSPR modes and adjust their resonance frequencies (wavelengths) separately through adjusting the individual particle geometry. Single particle with specifically designed geometry has the potential to provide a compact structure to realize LSPR-participated strong coupling, in contrasting to above mentioned strong coupling systems usually having complex structures.…”

Microstructure Engineering of Hexagonal Boron Nitride for Single‐Photon Emitter Applications

“…In addition, Häußler et al proposed that a fiber-based Fabry-Pérot cavity could be employed to enhance the photoemission of SPEs up to 50-fold and yield narrower linewidths (Figure 7f). Various cavity-quantum emitter systems have been realized, and coupling mechanisms have been addressed based on different physical models [62] However, focusing on 2D materials, especially h-BN, the coupling mechanism remains elusive and should be addressed in the future.…”

Ultrasensitive Refractive Index Sensing Based on Hybrid High-Q Metasurfaces

“…To be specific, generally two kinds of materials are widely applied for RI sensing. One is the metallic material that can sustain surface plasmon (SP) modes − that has high RIS due to the intense electric field enhancements caused by SP resonances. But also because the SP modes have large decays induced by metallic ohm loss, the plasmonic biosensor can hardly have a large Q .…”