Low-density quantum dots embedded in photonic-crystal nanocavities for single-photon generations

Abstract

An efficient single-photon source based on low-density InGaAs quantum dots in a photonic-crystal nanocavity is demonstrated. The single-photon source features the effects of photonic band gap, yielding a single-mode spontaneous emission coupling efficiency as high as beta=92% and a linear polarization degree up to p=95%. This appealing performance makes it well-suited for practical implementation of polarization-encoded schemes in quantum cryptography.