Fermi pencil beams and off-axis laser detection

Area of Science:

• Optics and Photonics
• Atmospheric Physics
• Radiative Transfer Theory

Background:

• Laser beam propagation through turbulent atmospheres presents significant challenges for remote sensing and optical communication.
• Accurate characterization of beam properties is crucial for understanding light-matter interactions in atmospheric media.

Purpose of the Study:

• To develop an analytic reconstruction method for determining the properties of narrow laser beams.
• To enable the characterization of beams propagating in turbulent atmospheric conditions.

Main Methods:

• Utilizing off-axis measurements based on wide-angle single scattering of light.
• Modeling light propagation using macroscopic approximations of radiative transfer equations (Fermi pencil beam or fractional Fermi pencil beam equations).

Main Results:

• A simplified procedure for reconstructing constitutive beam parameters is established.
• The method allows for the determination of the beam's direction of propagation.
• The location of the emitting source can be accurately identified.

Conclusions:

• The proposed analytic reconstruction method offers an efficient approach for characterizing laser beams in turbulent atmospheres.
• Off-axis scattering measurements combined with advanced radiative transfer models provide valuable insights into beam properties.