The Expected Performance of an Optical Pumping Light Source, and the Kinetics of Optical Pumping of 2³<i>S</i>₁³He

Abstract

A practical light source for optical pumping necessarily excites transitions other than those which it is desired should be excited. It is shown that a pumping light source for 2 3 S 1 3 He may be characterized by three parameters, which describe the transition rates for Δm = ±1, and 0, transitions under standard conditions. Expressions are derived relating these parameters to the geometry of the light source. The equation which describes the flow of angular momentum into 3 He is formulated, using these parameters, the light flux, the lifetime of the metastable atoms, and collisional mixing in the 2 3 P states. This equation is solved to give the polarization which may be attained, and the rate at which the polarization is built up. A modification of this equation is also given, which takes into account moderate trapping of resonance radiation. An expression is also derived which relates the polarization of 3 He to the intensity of the scattered pumping light.