Figure 1

(a) Definition of the angles $\mathit{\theta }$ and $\mathit{\varphi }$ as used in the text. (b) SEM image of the microwire under study. The measured radius is 500 ± 20 nm. The gray solid and dashed line materializes the microwire hexagonal cross section.Reuse & Permissions

Figure 2

Angle-resolved and polarization-resolved (right: TE; left: TM) room-temperature PL of microwire 1 (microwire with constant diameter). The emission intensity is color scaled and increases from black to yellow (black to white). (a) Angle $\mathit{\theta }$ resolution. The white dashed lines are the calculated dispersion of uncoupled HWGM modes. The white dashed-dotted lines represent the calculated exciton-polariton modes. (b) Angle $\mathit{\varphi }$ resolution. The labels “$\mathrm{mpn}$” on the left-hand side of the figure refer to the polariton mode quantum numbers (azimuthal $\mathit{m}$, and radial $\mathit{N}$) and polarization ($\mathit{p}$ $=$ TE or TM) according to the HWGM they derive from (calculated HWGM modes have their labels in italics).Reuse & Permissions

Figure 3

Spatially resolved TE-polarized emission spectrum along a 32-μm segment of microwire 2 (tapered microwire) at temperature (a) $\mathit{T}$ $=$ 70 K and (b) $\mathit{T}$ $=$ 300 K. Along this portion of the microwire, the inhomogeneous diameter (presently increasing from left to right) provides a natural way to continuously vary the exciton-photon detuning. ${\mathrm{S}}_1$–$S_5$ label the five visible polariton modes at 70 K. The $\Delta =(E_X,E_X-E_{\mathrm{LO}})$ energy range is shown by the white arrows. Red (dark gray) solid lines show the calculation of the phonon contribution to the polariton linewidth vs energy. (c) Pure exciton linewidth vs temperature [energy and position shown by the orange (gray) circle in (a)]. (d) Measured homogeneous linewidth of polariton mode S2 vs temperature [red (dark gray) round symbols], when its energy lies below Δ. The dashed blue (black) line plots the photon-escape contribution to the linewidth (100% contribution to the linewidth at 10 K). The homogeneous linewidths are obtained from angle-resolved measurement carried out in a region centered on $\mathit{L}$ $=$ 43 μm [green (light gray) circles in (a) and (b)].Reuse & Permissions