Observation of a hybrid state of Tamm plasmons and microcavity exciton polaritons.

SK. Shaid-Ur Rahman,Kathrin Sebald,Detlef Hommel,Sebastian Klembt,Jürgen Gutowski,Thorsten Klein

doi:10.1038/srep34392

Abstract

We present evidence for the existence of a hybrid state of Tamm plasmons and microcavity exciton polaritons in a II-VI material based microcavity sample covered with an Ag metal layer. The bare cavity mode shows a characteristic anticrossing with the Tamm-plasmon mode, when microreflectivity measurements are performed for different detunings between the Tamm plasmon and the cavity mode. When the Tamm-plasmon mode is in resonance with the cavity polariton four hybrid eigenstates are observed due to the coupling of the cavity-photon mode, the Tamm-plasmon mode, and the heavy- and light-hole excitons. If the bare Tamm-plasmon mode is tuned, these resonances will exhibit three anticrossings. Experimental results are in good agreement with calculations based on the transfer matrix method as well as on the coupled-oscillators model. The lowest hybrid eigenstate is observed to be red shifted by about 13 meV with respect to the lower cavity polariton state when the Tamm plasmon is resonantly coupled with the cavity polariton. This spectral shift which is caused by the metal layer can be used to create a trapping potential channel for the polaritons. Such channels can guide the polariton propagation similar to one-dimensional polariton wires.

Highlights

Exciton polaritons are half light, half matter bosonic quasiparticles, resulting from the strong light-matter coupling between the quantum well (QW) excitons and the cavity photons in a microcavity (MC)
We report on the experimental observation of a hybrid Tamm plasmons (TPs)-microcavity exciton polariton state in a ZnSe-based MC
We have experimentally demonstrated the existence of a hybrid state of the TP-microcavity exciton polariton by depositing a thin Ag film on top of a ZnSe-based monolithic microcavity

Summary

Results

Layer the hybrid mode exhibits two field maxima. One is located at the metal-DBR interface and the other at the center of the cavity (Fig. 3(b)). If the exciton (Xhh), cavity, and TP mode are nearly in resonance (Ehh ≈EC =ET at the top layer thickness of approximately 21 nm), the lowest hybrid mode will be red shifted by ΔE ≈ 13 meV with respect to the lower cavity polariton state without Ag (indicated by the horizontal dotted line). A confinement depth of ΔE = 3 meV can be obtained by utilizing a 16-fold top DBR where the cavity Q factor increases by a factor of 3.5 (see supplementary information Fig. S5) This value of ΔE is still one order of magnitude larger than that obtained for non-resonant modulation[21], where the TP mode is far detuned from the exciton polariton. In this context the hybrid metal-MC approach would be an interesting alternative choice

Discussion

Methods