Incorporating polaritonic effects in semiconductor nanowire waveguide dispersion

Abstract

We present the calculated and measured energy-propagation constant (E-β) dispersion of CdS nanowire waveguides at room temperature, where we include dispersive effects via the exciton-polariton model using physical parameters instead of a phenomenological equation. The experimental data match well with our model while the phenomenological equation fails to capture effects originating due to light-matter interaction in nanoscale cavities. Due to the excitonic-polaritonic effects, the group index of the guided light peaks close to the band edge, which can have important implications for optical switching and sensor applications.

Resolving Parity and Order of Fabry–Pérot Modes in Semiconductor Nanostructure Waveguides and Lasers: Young’s Interference Experiment Revisited

“…Using a similar approach as described above, we can also obtained the exact mode orders by solving the Maxwell's equations incorporating the boundary condition of continuous tangential fields at the nanowire surface while simultaneously satisfying the requirement of the cavity mode parity of the experimental results. 20 In conclusion, we have demonstrated that the parity and the mode order of F-P type cavity modes can be obtained in semiconductor nanoribbons and nanowires by performing angle-resolved μ-PL measurements. The even (odd) modes with symmetric (asymmetric) E-field distribution are clearly observed via an experimental configuration analogous to the Young's interference experiment in which the double slits are replaced by the two edges of the CdS nanoribbon (or two ends of the nanowire).…”

Low‐Threshold Nanolasers Based on Slab‐Nanocrystals of H‐Aggregated Organic Semiconductors

“…This is probably due to the formation of exciton-polaritons (EPs) as a result of strong coupling of excitons with cavity photons in the nanometer-scale SNC radial cavities, [23][24][25] although the actual mechanism needs to be further clarifi ed by detailed comparison of the dispersion in angular momentum space (in-plane wavevector k // , Figure 4 e) through angle-resolved characterizations (PL, absorption, and refl ection). [ 5 , 26 ] The group velocity refraction index, [ n − λ (d n/ d λ )] = 150, means that the signal velocity is only 1/150 of the light speed in vacuum, [ 23 , 24 ] enabling SNCs capable of propagating the polariton light and steering them on the nanometer scale.…”

Tailoring light–matter coupling in semiconductor and hybrid-plasmonic nanowires

“…These polaritonic effects on nanowire dispersion were first incorporated in a follow-up study by van Vugt et al .,[125] utilizing an equation for permittivity near two interacting resonances in place of the phenomenological model (Sellmeier equation) to explicitly capture changes near the close-lying A- and B-exciton resonances in CdS: $$\epsilon false(\omega false)={\epsilon }_b\left(1+\frac{{\omega }_{BL}^2-{\omega }_{AT}^2}{{\omega }_{BT}^2-{\omega }_{AT}^2}\frac{{\omega }_{AL}^2-{\omega }_{AT}^2}{{\omega }_{AT}^2-{\omega }^2-i\omega {\mathrm{\Gamma }}_A}+\frac{{\omega }_{AL}^2-{\omega }_{BT}^2}{{\omega }_{AT}^2-{\omega }_{BT}^2}\frac{{\omega }_{AL}^2-{\omega }_{AT}^2}{{\omega }_{BT}^2-{\omega }^2-i\omega {\mathrm{\Gamma }}_B}\right)$$ where ε b is the background dielectric constant, ω AT and ω AL are the A-exciton transverse and longitudinal resonance frequencies, ω BT and ω BL are the B-exciton transverse and longitudinal resonance frequencies, Γ A the A–exciton damping and Γ B the B–exciton damping. In utilizing literature values for the background dielectric constant and damping, only the longitudinal and transverse frequencies remain variable.…”