Laser Propagation, Scattering and Identification

When we see a laser beam, it is because the light scattered off air molecules in the atmosphere and some of it was in the direction of our eye. The distribution of the scattered light can be predicted well in many situations. In this paper, we use a Mie scattering model to invert a received light signal and then determine the laser’s location, strength and other properties. 

Depiction of a solution to the radiative transfer equations for atmospheric scattering of laser light (red arrow). The colors on each sphere represent the intensity of scattered light an observer sees at that location and in every direction.

It was found to be necessary to include the effect of polarization in order to extract the desired description of the laser. The figure below shows how the polarization vector changes with scattering angle for linearly polarized light.

This work was published in Inverse Problems in Science and Engineering:

Inversion Methods for Laser Parameter Extraction with Phenomenological Model Based on Off-Axis Sensor Measurements