PICOSECOND RAMAN-SPECTROSCOPY USING A STREAK CAMERA

A Raman measuring system using a streak camera has been constructed. T his system consists of a picosecond pulsed laser, an astigmatism-corre cted spectrograph, and a streak camera. It enables two-dimensional mul tichannel detection (time and frequency) of Raman scattering with time resolution as high as 10 ps (without deconvolution). The system was f irst applied to fluorescence background rejection. Raman spectra of be nzene containing a trace amount of Rhodamine 640 were measured. The im provement factor of the Raman-to-fluorescence intensity ratio was esti mated as 281, compared with the time-integrated cw measurement. Second , the system was used for picosecond time-resolved Raman spectroscopy. Nanosecond probing laser pulses were used with picosecond pumping. Ra man scattering at each delay time was time-resolved and detected by th e streak camera. Time-resolved Raman spectra of benzophenone at delay times ranging from -1.25 ns to 1.5 ns were obtained from one single me asurement. These results indicate that, if properly designed and prope rly combined with a suitable optical setup, a streak camera has very h igh potential for Raman spectroscopy.