Scanning interferometer stabilized by use of Pancharatnam's phase.

Time-resolved interferometric optical experiments demand both active stabilization of the relative phase between phase-locked pulses and continuous scanning of their time delay over a wide range. We describe a novel method that meets the above requirements in a convenient and simple way by use of the accumulated phase according to Pancharatnam [Proc.Indian Acad.Sci.Sect.A 44, 247 (1956)].