Collisional Depolarization in Caesium (6S 1/2 -7P 1/2) by Noble Gases Using Three Pulse Echoes

Three pulse echoes are used to measure the collisional destruction of Zeeman coherences in caesium (6S1/2−7P1/2) perturbed by low pressures of helium, argon and xenon. Anomalously large collision rates associated with the 6S1/2 ground state are obtained. It is suggested that the transfer of Zeeman coherences by spontaneous decay plays a role.