  We propose an implementation of a CNOT quantum gate for quantum computing
based on a patterned microcavity polariton system, which can be manufactured
using the modern technological facilities. The qubits are encoded in the spin
of polaritons. The structure consists of two wire cavities oriented at 45
degrees with a micropillar between them. The polariton spin rotates due to the
Longitudinal-Transverse splitting between polarisation eigenstates in the
wires. In the pillar, the optically generated circularly polarised polariton
macrooccupied state plays the role of the control qubit. Because of the
spin-anisotropic polariton interaction, it induces an effective magnetic field
along the Z-direction with a sign depending on the qubit value.
