Video sampling: a new low-cost method of capturing fast repetitive processes

A new method for measurement, documentation and visualization of fast repetitive processes is presented. The method extends the principle of sampling--as is currently used in measuring fast repetitive electrical signals--to video recording; using a fast external shutter in front of an unmodified, free running, standard CCIR or EIA video camera. The result is a slow-motion display that can be viewed continuously, recorded on standard video equipment or further processed like any other video signal. In a number of experiments in the field of nonlinear optics, exposure intervals of down to 100 nanoseconds at a full-frame repetition rate of 25 Hz were used, thus slowing down the time scale by a factor of 400,000. Additional features increase the efficiency, which is otherwise limited by the short exposure time, increase the maximum time-scaling factor and facilitate polarization-resolved measurements.