Tuning nanoscale plasmon–exciton coupling via chemical interface damping

Abstract

Here, we demonstrate how chemical interface damping (CID) influences the nanoscale plasmon–exciton coupling strength.

Plasmon–Exciton Interaction at the Nanoscale: Silver Is More “Precious” than Gold!

“…21 For the same reason, the contribution of chemical interface dephasing (CID) too is negligible and similar for both the nanoprisms as both are capped by CTA + bilayers. 22 Considering all these factors, it can be concluded that the decay rate of the excited LSP mode for the Ag NP is much faster than for the Au NP, which makes the LSPR spectrum of the silver nanoprism broader compared to the gold nanoprism as obtained in the single-particle experiments. Next, we recorded the single-particle dark-field scattering spectra of the plexciton hybrids of the Au and Ag nanoprisms.…”

“…Since the LSPR positions of both Au NP and Ag NP were chosen to be resonant with the transparency dip position shown by Cy78 J-aggregate while coupled to a plasmonic system, our ensemble-level extinction measurements of the plexciton hybrids directly allows us to estimate the Rabi splitting (satisfying the zero-detuning condition). ,, Using different gold nanorods it has been shown earlier that an increase in plasmon linewidth due to radiation damping weakens the plasmon–exciton coupling . Increase in mode-volume too has been found to have the same effect on plasmon–exciton coupling strength. ,, In different studies we demonstrated that effective plasmon mode-volume ( V m ) dominates over plasmon decay effects (radiation damping or electron surface scattering damping) in controlling plasmon–exciton coupling. ,, If the geometric volume accurately represents V m , then the plasmon mode-volume of the silver nanoprism should be greater than that of the gold nanoprism. , On the other hand, if the mode-volume is only a fraction of the geometric volume, a precise calculation of the actual plasmon mode-volume is necessary. If the larger geometric volume-induced larger radiation damping alone would control the plasmon–exciton coupling strength, then our Ag nanoprism would show much weaker plasmon–exciton coupling compared to that of its gold counterpart.…”

“…12 Increase in modevolume too has been found to have the same effect on plasmon−exciton coupling strength. 12,19,22 In different studies we demonstrated that effective plasmon mode-volume (V m ) dominates over plasmon decay effects (radiation damping or electron surface scattering damping) in controlling plasmon− exciton coupling. 12,25,28 If the geometric volume accurately represents V m , then the plasmon mode-volume of the silver nanoprism should be greater than that of the gold nanoprism.…”

“…On the other hand, the coupling strength is also dependent on the plasmon–exciton energy exchange rate. Various factors, such as large electric field enhancement, , smaller plasmon mode-volume, , lower nonradiative loss, , high local density of states, , high oscillator strength of the exciton, , etc., are expected to promote greater plasmon–exciton energy exchange rate. Recent studies demonstrated how plasmon decoherence rate, , mode-volume of the nanostructure, , and LDOS , can be tailored by changing the size and shape of the nanostructures that can further modify plasmon–exciton coupling strengths.…”

“…Various factors, such as large electric field enhancement, , smaller plasmon mode-volume, , lower nonradiative loss, , high local density of states, , high oscillator strength of the exciton, , etc., are expected to promote greater plasmon–exciton energy exchange rate. Recent studies demonstrated how plasmon decoherence rate, , mode-volume of the nanostructure, , and LDOS , can be tailored by changing the size and shape of the nanostructures that can further modify plasmon–exciton coupling strengths. In addition to the size, shape, and surrounding medium of the nanostructure, the optical properties of the plasmon-supporting metal nanoparticles are greatly influenced by the frequency-dependent dispersive nature of the plasmonic metals.…”