Calculation of Faraday effect dispersion at two-photon resonance

N. S. Shiren

Давид Николаевич Клышко, B. V. Polkovnikov

Ilja Gerhardt

The Macaluso-Corbino effect describes the optical rotation of light in the spectral proximity to an atomic resonance. One use of this effect is narrowband optical filtering. So-called Faraday filters utilize the difference of the two components of the refractive indices, which are split by the Zeeman effect in a longitudinal magnetic field. This allows for a net rotation of a linearly polarized input beam within the medium. Placing it between crossed polarizers therefore only allows light near resonance to pass. Since any resonant spectrum implies anomalous dispersion on resonance, these filters are often characterized as being based on this anomalous dispersion. This Letter analyses to what extent the anomalous dispersion and the anomalous rotation are relevant for Faraday filters. Considering the sign of the anomalous rotation introduces a strict criterion if the filter is operated in the line center or in the spectral wing of an atomic resonance.

Joanna A. Zielińska

[ANGLÈS] We describe experimental results on a novel optical filter based on the FADOF (Faraday Anomalous Dispersion Optical Filter) principle, and its application to production of atom-resonant entangled photon pairs at the D_1 line of atomic rubidium. The filter uses natural-abundance rubidium vapor in an axial magnetic field to produce Faraday rotation up to pi/2 in the transparent regions adjacent to Rb absorption features. When the Faraday rotator is placed between crossed polarizers, the resulting system shows a 400 MHz FWHM transmission window with 70% peak transmission, and out-of-band rejection up to 10^5. Using this device we demonstrate selection of atom-resonant photon pairs from a type-I cavity-enhanced spontaneous parametric downconversion source (CESPDC). We also present an exact calculation of the time correlations, i.e., the g^(2)(T), of photons from the CESPDC. This is the first time fully-indistinguishable atom-resonant photon pairs have been observed.

Joanna A. Zielińska

[ANGLÈS] We describe experimental results on a novel optical filter based on the FADOF (Faraday Anomalous Dispersion Optical Filter) principle, and its application to production of atom-resonant entangled photon pairs at the D_1 line of atomic rubidium. The filter uses natural-abundance rubidium vapor in an axial magnetic field to produce Faraday rotation up to pi/2 in the transparent regions adjacent to Rb absorption features. When the Faraday rotator is placed between crossed polarizers, the resulting system shows a 400 MHz FWHM transmission window with 70% peak transmission, and out-of-band rejection up to 10^5. Using this device we demonstrate selection of atom-resonant photon pairs from a type-I cavity-enhanced spontaneous parametric downconversion source (CESPDC). We also present an exact calculation of the time correlations, i.e., the g^(2)(T), of photons from the CESPDC. This is the first time fully-indistinguishable atom-resonant photon pairs have been observed.

David A. Holm, M. Sargent