Fog picture

Physicists Clear the Air With a Sweet Frickin' Laser Beam

Fast laser pulses produce a shock wave in air that pushes water vapor aside. That clears channels in clouds for transmitting optical data from satellites.

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This work was first described in Optics Express. 2020, vol. 28, no. 8, p. 11463

Molecular quantum wakes for clearing fog

SCHROEDER, Malte Christian, et al.


High intensity laser filamentation in air has recently demonstrated that, throughplasma generation and its associated shockwave, fog can be cleared around the beam, leaving anoptically transparent path to transmit light. However, for practical applications like free-spaceoptical communication (FSO), channels of multi-centimeter diameters over kilometer ranges arerequired, which is extremely challenging for a plasma based method. Here we report a radicallydifferent approach, based on quantum control. We demonstrate that fog clearing can also beachieved by producing molecular quantum wakes in air, and that neither plasma generationnor filamentation are required. The effect is clearly associated with the rephasing time of therotational wave packet in N2. Pump excitation provided in the form of resonant trains of 8 pulsesseparated by the revival time are able to transmit optical data through fog with initial extinctionas much as -6dB.


arXiv: 2004.04056