Coherent beam combining in atmospheric channels using gated backscatter.

Area of Science:

• Optical physics
• Atmospheric optics
• Laser physics

Background:

• Turbulent atmospheres disrupt laser beam coherence and focusing.
• Optical phased arrays (OPAs) require precise beam control for effective operation.
• Existing methods for atmospheric laser beam correction are often complex and require target feedback.

Purpose of the Study:

• To introduce and numerically demonstrate the concept of atmospheric channels for laser beam guidance.
• To present a novel method for coherent beam combining of OPAs in turbulent atmospheres.
• To show how atmospheric channels can improve OPA performance without target feedback.

Main Methods:

• Utilizing the sparse spectrum harmonic augmentation method for simulations.
• Numerically demonstrating the guiding properties of atmospheric channels.
• Developing a channel probing and phase measurement technique using aerosol backscattered radiation.
• Employing electronic focusing, scanning, and time gating of the OPA.

Main Results:

• Atmospheric channels exhibit unique properties: guiding light, gathering multiple sources, and maintaining relative phase.
• The proposed method successfully demonstrated coherence improvement of OPA elements.
• Energy refocusing at the channel location was achieved, increasing power in the bucket.
• The technique effectively bypasses the need for target feedback.

Conclusions:

• Atmospheric channels offer a promising approach for robust laser beam control in turbulent environments.
• The developed method enhances OPA capabilities for applications requiring precise laser delivery.
• This research paves the way for improved laser communication and remote sensing through atmospheric channels.