Real-time oscilloscope observation of an ultrafast photodiode response to mode-locked laser pulses

Pulses of 100 ps full width at half maximum (FWHM) have been displayed on a direct current to 5-GHz real-time oscilloscope. The 100-ps duration includes contributions from the oscilloscope, the photodetector, and the laser pulse,Maximum current in the linear regime of the photodiode is ≈3 amperes so that electric pulses of ≈70 ps FWHM and ≈150 volts can be obtained with the laser-detector combination. Results of a simple optical method for determining the exposure time of high-speed electronic cameras are also briefly given.