Continuous frequency-domain multiplexing of heralded single-photon sources

Single-photon sources are an important tool for experiments in quantum optics and quantum information [1]. Heralded single-photon sources based on non-linear processes such as parametric down-conversion are ubiquitous. However, significant limitations arise due to the probabilistic nature of photon pair emission, as well as the possibility of generating more than one photon per pump pulse. In a technique known as multiplexing [2-3], the probability of generating a single photon can be increased by switching the output from multiple sources into a single channel.

We present a frequency-multiplexed single-photon source which increases the single-photon delivery probability without increasing multi-photon noise. This is accomplished by spectral detection and controlled frequency translation that both have a resolution greater than the single-photon bandwidth. In addition, we have measured the purity of the heralded photon by Hong-Ou-Mandel (HOM) interference showing a non-classical visibility of ~64%.

[1] E. Knill, R. Laflamme, and G. J. Milburn, Nature 409, 46 (2001)
[2] A. L. Migdall, D. Branning, S. Castelletto, Phys. Rev. A, 66, 053805 (2002)
[3] T. B. Pittman, B. C. Jacobs, J. D. Franson, Phys. Rev. A, 66, 042303 (2002)