We propose a single-photon router using a single atom with an inversioncenter coupled to quantum multichannels made of coupled-resonator waveguides.We show that the spontaneous emission of the atom can direct single photonsfrom one quantum channel into another. The on-demand classical field perfectlyswitches-off the single-photon routing due to the quantum interference in theatomic amplitudes of optical transitions. Total reflections in the incidentchannel are due to the photonic bound state in the continuum. Two virtualchannels, named as scatter-free and controllable channels, are found, which arecoherent superpositions of quantum channels. Any incident photon in thescatter-free channel is totally transmitted. The propagating states of thecontrollable channel are orthogonal to those of the scatter-free channel.Single photons in the controllable channel can be perfectly reflected ortransmitted by the atom.
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