Optical Pumping

The central theme of ‘optical pumping’ is the transfer of angular momentum. Circularly polarized light carries angular momentum, and resonant light can transfer this angular momentum to the atoms in a vapor sample. This technique, combined with the quantum-mechanical properties of atoms’ ground states, makes possible a host of applications of a deceptively simple optical technique.

Optical pumping is historically interesting for its ‘late’ discovery—this non-laser phenomenon could have been discovered in the 1930’s. But since its invention in the 1950’s, it has remained a technique of continuing interest for highly-sensitive magnetometry, and for atomic frequency standards. It’s also a fine tool for motivating students to appreciate the details of atomic fine- and hyperfine-structure.

This workshop will use the ‘optical bench’ topology of a TeachSpin apparatus to show in detail the instrumental requirements for this technique. Participants will learn how to set up, align, and optimize an optical-pumping apparatus. They will use it to detect driven radio-frequency quantum transitions in real time, and apply that capability to the measurement of weak magnetic fields.