We demonstrate high optical depths (50 +/- 5) that last for hours in rubidium-filled hollow-core photonic bandgap fibers, which represent a 1000x improvement over the operation times previously reported. We investigate the vapor generation mechanism using both a continuous wave and a pulsed light source, and find that the mechanism for generating the rubidium atoms is primarily due to thermal vaporization. The continuous generation of large vapor densities should enable measurements at the single-photon level by averaging over longer time scales. (C) 2015 Optical Society of America
展开▼