Broad-band laser optical pumping of Rb for the creation of nuclear polarisation in ~3He

摘要

A large volume (30 cm~3) of dense (up to 10~15 cm~-3) Rb vapourwas pumped optically by a highpower laser diode array. The conditions for the propagation of high-power broad-band optical pump radiationthrough an optically dense medium were examined. A spectroscopicmethod was developed for determination of the polarisation of Rb. Thedependence of the polarisation of Rb on its vapour pressure wasinvestigated at buffer gas pressures of 1, 8, and 13 bar. Underoptimal conditions a 15-W diode laser made it possible to polarise atleast 10~18 of~3 He atoms per second during collisions between Rb and~3He atoms, sufficient for the creation of an efficient neutronpolariser.