Complete architecture of integrated photonic circuits based on and and not logic gates of exciton polaritons in semiconductor microcavities

We present a complete photonic logic gate architecture in a compact solid-state system, making use of the nonlinear and spintronic properties of exciton polaritons in semiconductor microcavities. The dynamics of the system is modeled using the spinor Gross-Pitaevskii equations, and it is shown that the proposal fulfills all the necessary criteria for fully functioning information processing devices without the use of any external electric fields.

Figure 1

Figure (a) shows the confinement potential $V\left(\mathbf{r}\right)$ proposed for the not gate. The darker area corresponds to a potential of $V\left(\mathbf{r}\right)=0$, while the white area corresponds to $V\left(\mathbf{r}\right)=5\text{meV}$. Similarly, plot (b) shows the potential used for the and gate. Figure (c) shows the bistability at the nodes of the system. The dashed vertical line corresponds to the background intensity given by $|F_s{|}^2$. Points C and B correspond to the polariton density when a pulse ${\mathcal{P}}_s$ is applied and after it has finished, respectively.

Figure 2

Evolution of the circular polarization degree $\rho$ of the system at different times. In the first row we can see the system at the time $t_0=60\text{ps}$, when the input pulse is sent writing the state of the first node. The pulse has a duration of $\tau =18\text{ps}$; therefore for the successive times shown the system is evolving without the pulse. The state reached at $t=210\text{ps}$ is a stable state.

Figure 3

We show the dynamics of the and gate for different inputs; each row represents a different process where the input was changed according to the inset in Fig. 1b, i.e., row 1 is the process I, row 2, process II, etc. In the first column we show the time where the pulse is sent to write the state of the input nodes. For the successive times shown the system is evolving without the input pulse.