Spin and density patterns of polariton condensates resonantly excited in strained planar microcavities with a nonuniform potential landscape

Spin and density patterns of exciton-polariton condensates in strained planar cavities with a nonuniform energy landscape are shown to undergo fast nonequilibrium transformations under the conditions of pulsed resonant excitation. Maxima in the spatial distribution of condensate density shift from the potential humps to the traps, which is accompanied by a linear-to-circular polarization conversion at each space point. The transitions are explained within the framework of modified Gross-Pitaevskii equations with account taken for the spin-anisotropic polariton-polariton interaction and the spatial dependence of the polariton energy.

Figure 1

Time and spatial dependencies of the pump pulse (a), and measured (b) and modeled (c) transmission signal at low pump densities $P\approx {10}^{-1}{P}_{\mathrm{crit}}$. White traces in (a), (b), and (c) are the pump time profile, the spatial profile of the transmitted signal at $t=0$, and the profile of the potential landscape used for modeling, correspondingly.

Figure 2

Measured [(a)–(c)] and calculated [(d)–(f)] time and spatial distributions of the transmission signal intensity [(a), (d)] and its degrees of circular [(b), (e)] and linear [(c), (f)] polarizations at $P\approx 1.5P_{\mathrm{crit}}$. White trace is the pump time profile.

Figure 3

Measured (a) and calculated (b) spatial distributions of the signal intensity and its degree of circular polarization at $t=-30$, $-15$, and 0 ps at $P\approx 1.5P_{\mathrm{crit}}$. These are the slices of the data shown in Fig. 2. Dashed line is the pump profile. Time dependencies of the signal at $x=x_{\max }\approx -9$ $\mu$m and $x=x_{\min }\approx 0$ are shown in Fig. 4.

Figure 4

Time dependencies of the signal at $x_{\max }=-9\mu$m [(a)–(d)] and at $x_{\min }=0$ [(e)–(h)] recorded in the ${\sigma }^{\pm }$ (left column) and ${\pi }_{x,y}$ (right column) polarizations at $P\approx 1.5P_{\mathrm{crit}}$. Panels (a), (b), (e), (f) and panels (c), (d), (g), (h) represent measured and modeled data, respectively.

Figure 5

Steady-state response functions calculated within the one-mode approximation. (a) and (b) correspond to the pump detunings typical of the potential humps and traps, respectively. Colors represent the degree of circular polarization of intracavity field. Vertical lines indicate the pump power $P=1.5P_{\mathrm{crit}}$ at which the modeled counterparts of Figs. 2, 3, 4 were obtained.