Precise and Rapid Detection of Optical Activity for Accumulative Femtosecond Spectroscopy

We present a fast and sensitive polarimeter combining common-path optical heterodyne interferometry and accumulative spectroscopy to detect rotatory power. The sensitivity of rotatory detection is determined to be 0.10 milli-degrees for a measurement time of only one second and an interaction length of 250 μm. Its suitability for femtosecond studies is demonstrated in a non-resonant two-photon photodissociation experiment