High-resolution Raman spectra with femtosecond pulses: an example of combined time- and frequency-domain spectroscopy.

Frequency-domain spectroscopy requires long pulses, whereas time-domain spectroscopy requires short pulses. This Letter demonstrates both theoretically and experimentally that simultaneous detection in frequency and time generates well-resolved spectra using intermediate-length pulses. In the case of coherent Raman spectroscopy, typical femtosecond pulses lie between the time and frequency domains. To demonstrate this method, a high-resolution Raman spectrum of nitrobenzene is obtained from 60 fs pulses. Phase control, pulse shaping, or pulses of widely differing duration are not required.