  In Impulsive Stimulated Raman Scattering vibrational oscillations, coherently
stimulated by a femtosecond Raman pulse, are real time monitored and read out
as intensity modulations in the transmission of a temporally delayed probe
pulse. Critically, in order to retrieve broadband Raman spectra, a fine
sampling of the time delays between the Raman and probe pulses is required,
making conventional ISRS ineffective for probing irreversible phenomena and/or
weak scatterers typically demanding long acquisition times, with signal to
noise ratios that crucially depend on the pulse fluences and overlap
stabilities. To overcome such limitations, here we introduce Chirped based
Impulsive Stimulated Raman Scattering (CISRS) technique. Specifically, we show
how introducing a chirp in the probe pulse can be exploited for recording the
Raman information without scanning the Raman-probe pulse delay. Then we
experimentally demonstrate with a few examples how to use the introduced scheme
to measure Raman spectra.
