RESUMEN
We show that the group velocity of a probe pulse in an ensemble of Λ-type atoms driven by a quantized cavity mode depends on the quantum state-of-the input probe pulse. In the strong-coupling regime of the atom-cavity system the probe group delay is photon-number selective. This can be used to spatially separate the single photon from higher photon-number components of a few-photon probe pulse and thus create a deterministic single-photon source.
RESUMEN
We show that a pair of quantized modes interacting with a spectrally broadened ensemble of Lambda-type atoms is analogous to an ensemble of two-level systems coupled to a bosonic reservoir. This enables an irreversible photon transfer between photon modes. The reservoir can be engineered which allows the observation of effects such as the Zeno and anti-Zeno effect, the destructive interference of decay channels, and the decay in a squeezed vacuum. We also consider a photon diode, i.e., a device which directs a single photon from any one of two input ports to a common output port.
RESUMEN
We investigate the storage of light in an atomic sample with a Lambda-type coupling scheme driven by optical fields at variable two-photon detuning. In the presence of electromagnetically induced transparency (EIT), light is stored and retrieved from the sample by dynamically varying the group velocity. It is found that for any two-photon detuning of the input light pulse within the EIT transparency window, the carrier frequency of the retrieved light pulse matches the two-photon resonance frequency with the atomic ground state transition and the control field. This effect which is not based on spectral filtering is investigated both theoretically and experimentally. It can be used for high-speed precision measurements of the two-photon resonance as employed, e.g., in optical magnetometry.