High speed time-resolving imaging

In order to obtain a high depth resolution, not only the use of a fast shutter, but also the use of a fast modulated chirped pulse is necessary. A chirped pulse of wide spectrum range is necessary, therefore a wide band shutter is also needed. Shutters faster than CS/sub 2/ were realized using other materials such as glasses or organic dyes. We applied the technique of fast shutter, which uses optical Kerr effect in gain medium and two perpendicularly polarized pump pulses in the picosecond region, to the femtosecond region, successfully. The technique made possible a femtosecond amplifying optical Kerr gate. A setup for ultra time-resolved spectroscopic imaging is shown. The experimental result shows that the peak transmission of 160%, which is more than 20 limes larger than that of the conventional CS/sub 2/ Kerr gate. The transient spectra with regard to each delay time are about 60 nm. Using this new technique, ultrafast time-gated spectroscopic imaging is experimentally achieved.