INTERFERENCE-FRINGES BETWEEN 2 SEPARATE LASERS

In a modem, generalized version of Young's two-slit experiment, it is shown that two separate pulsed lasers can generate visually observable, transient interference fringes of high contrast under the simple and obvious condition that the temporal and spectral structures of the interfering pulses overlap. In a second experiment, a picosecond streak camera allows the observation of spatio-temporal interference fringes between two waves having different frequencies.