Observation of femtosecond laser pulses propagation in non-uniform optical media as form of motion picture

Abstract

We demonstrate spatially and temporally continuous motion pictures of three-dimensional image of femtosecond light pulses propagating in non-uniform optical media. Light-in-flight recording by holography is applied to record the motion pictures. To record the three-dimensional image of the light propagation, a weakly diffusive optical medium with adequate volume made by gelatin jelly is introduced to the recording optical setup of the holography. A 226-femtosecond light pulse is incident into a graded-index medium consisting of gelatin jelly and sugar in the recording process. Then the recorded hologram is illuminated by a continuous wave laser operated at 728nm wavelength, which is the same as that of the laser pulse used in the recording, then we can clearly observe propagation of light pulse gradually curving. Also a 226-femtosecond light pulse is incident into a diffraction grating located in a uniform and diffusive medium in the recording process. Then we can observe diffraction of light pulse which split into three pulses and drastically changing the propagation direction.