Polarization controlled nonlinear transmission of light through semiconductor microcavities

We report on a pronounced nonlinear optical effect in a GaAs microcavity operating in the strong-coupling regime: cavity transmission in circular polarization is found to be much stronger than in linear polarization. This behavior has its origin in the spin-dependent repulsive interaction between exciton polaritons. Quantitative analysis allows estimating the strength of interaction between polaritons with parallel spins. The observed effect shows the potentiality of microcavities for circular polarization sensing essential for transmission of polarization encoded signals.

Figure 1

(Color online) The energies of the lower and upper polariton modes, as functions of the detuning between exciton and cavity modes, obtained from transmission spectra. Solid lines are fit within the coupled oscillators model (a). Transmission spectra at (b) 20 and (c) $200\mu \text{W}$ in linear (squares) and circular (circles) polarizations. Solid lines show the results of calculation using the transfer-matrix method.

Figure 2

(Color online) Polarization dependence of the transmission intensity at the lower polariton branch as a function of incident power. Squares stand for the circular and circles for the linear polarization, solid lines are guides for eyes. The data are taken at negative detuning $\delta =-1\text{meV}$.

Figure 3

(Color online) (a) and (b) Measured and (d) and (e) calculated maps of the (a) and (d) total $\left(T_c+T_l\right)$ and (b) and (e) normalized differential transmission $\left(T_c-T_l\right)/\left(T_c+T_l\right)$ also referred to as the mixed dichroism. (c) Measured and (f) calculated transmission spectra in linear and circular polarizations at the position indicated by the black line. The spectra have been measured at $200\mu \text{W}$ excitation power. The parameters of calculation are given in the text.

Figure 4

(Color online) Effect of the exciton blueshift on the (a) energies and (b) line-widths of the exciton-polariton eigenstates in microcavities (scheme). The thin solid lines correspond to the linear regime (no blueshift). The thick solid lines indicate the positions and broadenings of the polariton modes in the nonlinear regime, when the exciton resonance is blueshifted.