title: Proposed Fraunhofer-wavelength atomic filter at 534.9 nm.
abstract: A new atomic filter is proposed. It operates at 534.9 nm. The new filter offers two important advantages for openchannel laser communications. First, its wavelength matches the output of the frequency-doubled Nd:BEL laser. Second, the filter overlays a solar Fraunhofer line, thereby offering intrinsic sunlight suppression. Ultranarrowband optical filtering takes place within the singlet manifold of neutral-calcium vapor. Excellent filter properties are deduced from spectroscopic examination of the atomic system. A novel feature of the new filter is the potential for greater-than-unity internal photon conversion.
authors.forename: J A
authors.initials: JA
authors.lastname: Gelbwachs