Ultralow-power nonlinear optics using tapered optical fibers in metastable xenon

Abstract

We demonstrate nanowatt-level saturated absorption using a sub-wavelength diameter tapered optical fiber (TOF) suspended in a gas of metastable xenon atoms. This ultralow-power nonlinearity is enabled by a small optical mode area propagating over a relatively long distance through the Xe gas. The use of inert noble gasses in these kinds of TOF experiments may offer practical advantages over the use of reactive alkali vapors such as rubidium.