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

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 β=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. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]