Light-in-flight imaging

Light was first captured in its flight by N. Abramson in 1978,[3] who used a holographic technique to record the wavefront of a pulse propagating and being scattered by a white-painted screen placed in its path.

[6][7] Light can also be captured in motion in a scattering medium using a streak camera that has picosecond temporal resolution, thus removing the need for interferometry and coherent illumination but requires additional hardware to raster scan the two-dimensional (2D) scene, which increases the acquisition time to hours.

[8][9] A few other techniques possess the temporal resolution to observe light in motion as it illuminates a scene, such as photonic mixer devices based on modulated illumination, albeit with a temporal resolution limited to a few nanoseconds.

[10] Alternatively, time-encoded amplified imaging can record images at the repetition rate of a laser by exploiting wavelength-encoded illumination of a scene and amplified detection through a dispersive fibre, albeit with 160 ns temporal and spatial resolution.

[12] In 2015 a method to visualize events evolving on picosecond time scales based on single-photon detector arrays has been demonstrated.

500 ps laser pulse propagation in air visualized by a single-photon detector arrays [ 1 ]
A video demonstrating a superluminal light-in-flight observation captured with megapixel SPAD camera [ 2 ]