title: Ultrahigh and persistent optical depths of cesium in Kagomé-type hollow-core photonic crystal fibers.
abstract: Alkali-filled hollow-core fibers are a promising medium for investigating light-matter interactions, especially at the single-photon level, due to the tight confinement of light and high optical depths achievable by light-induced atomic desorption (LIAD). However, until now these large optical depths could only be generated for seconds, at most once per day, severely limiting the practicality of the technology. Here we report the generation of the highest observed transient (>10(5) for up to a minute) and highest observed persistent (>2000 for hours) optical depths of alkali vapors in a light-guiding geometry to date, using a cesium-filled Kagomé-type hollow-core photonic crystal fiber (HC-PCF). Our results pave the way to light-matter interaction experiments in confined geometries requiring long operation times and large atomic number densities, such as generation of single-photon-level nonlinearities and development of single photon quantum memories.
authors.forename: Krzysztof T
authors.initials: KT
authors.lastname: Kaczmarek
authors.forename: Dylan J
authors.initials: DJ
authors.lastname: Saunders
authors.forename: Michael R
authors.initials: MR
authors.lastname: Sprague
authors.forename: W Steven
authors.initials: WS
authors.lastname: Kolthammer
authors.forename: Amir
authors.initials: A
authors.lastname: Feizpour
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Ledingham
authors.forename: Benjamin
authors.initials: B
authors.lastname: Brecht
authors.forename: Eilon
authors.initials: E
authors.lastname: Poem
authors.forename: Ian A
authors.initials: IA
authors.lastname: Walmsley
authors.forename: Joshua
authors.initials: J
authors.lastname: Nunn