Diffusion of Rubidium Vapor through Hollow-Core Fibers for Gas-Phase Fiber Lasers

This work examines the diffusion of rubidium through a small diameter tube alone and in the presence of noble gases. A fluid dynamics analysis is investigated to aid in choosing a method for transferring atomic rubidium vapor that is reliable and efficient. Solutions to the time dependant ordinary differential equation describing the experimental flow properties of the system reveal more precise outcomes than previously practiced routines. Resolved viscosities and Poiseuille flow theory velocity profile distributions are characterized for noble gas carriers of the rubidium vapor. Applying Reynolds Numbers to the flow experiments provides pressure differential boundaries that are employed in the successful rubidium vapor transfer process. Atomic spectroscopy is demonstrated through the use of a rubidium D1 resonate diode laser to record an absorption spectrum and extract alkali vapor densities that successfully propagated through a 12 cm long capillary tube with a 500 ?m inner diameter.