Highly Efficient Generation of Entangled Photons by Controlling Cavity Bipolariton States

We theoretically investigate entangled-photon generation via a biexciton in a planar microcavity. Owing to strong exciton-photon coupling, the biexciton in the cavity produces a bound two-cavity-polariton state (cavity bipolariton). Entangled photons are generated by the cascade decay of the cavity bipolariton. We propose a novel scheme for highly efficient entangled-photon generation by controlling the cavity bipolariton states. It is shown that highly efficient generation can be achieved when a weak cavity bipolariton, formed by a biexciton and unbound cavity polaritons, is realized.

Figure 1

(a) Schematic of entangled-photon generation from a cavity bipolariton. (b) Example of eigenenergies for $N=1251$, $t=0.149E_{X_0}$, $L=219a$, and ${\Delta }_B=\hslash g_0=0.011E_{X_0}$. Dotted lines are the dispersion curves for the cavity and bare exciton.

Figure 2

$G^{(2)}$ as a function of $\overline{g}$ for six detection angles $\theta$.

Figure 3

(a) $E_{2p}/E_{X_0}$ as a function of $\overline{g}$. Dashed lines are the energies of the bare biexciton and noninteracting polaritons. (b) Probability amplitudes of a biexciton $|⟨B|2p⟩{|}^2$.

Figure 4

(a) $E_{2p}/E_{X_0}$ as a function of $\delta$. (b) Enhancement factor $\eta$ as a function of $\delta$ for $\theta =5°$.