Cs Faraday optical filter with a single transmission peak resonant with the atomic transition at 455 nm.

We demonstrate a Cs FADOF (Faraday anomalous dispersion optical filter) with a single transmission peak resonant with the 6S(1/2), F = 4 → 7P(3/2), F' = 3, 4, 5 transition at 455 nm. The filter achieves a single peak transmission of 86%. With the technique of saturated absorption spectra, we obtain the bandwidth of the single peak, which is 1.5 GHz. While most of other FADOFs operate at frequencies far from absorption, the filter we have realized can provide light exactly resonant with atomic transitions with a high transmission. We also find that, at a particular temperature, we can achieve a single transmission peak rather than many peaks far from absorption by changing the strength of magnetic field. This technique can also be applied to other alkali atoms.