Frequency-domain interferometer for femtosecond time-resolved phase spectroscopy

In femtosecond absorption spectroscopy, by the pump-probe technique with a white-light continuum difference transmission spectra (DTS) can be obtained by a single-shot measurement in principle. On the other hand, in femtosecond phase spectroscopy, which should be complementary to femtosecond absorption spectroscopy, there have been no methods so far by which difference phase spectra (DPS) can be obtained by a single-shot measurement.