Demonstration of controlled spatial incoherence for beam smoothing.

Area of Science:

• Optics and Photonics
• Laser Physics
• Beam Control

Background:

• High-energy laser systems require precise beam control to mitigate far-field nonuniformity.
• Random spatial phase modulation can introduce undesirable intensity variations in the laser beam.

Purpose of the Study:

• To demonstrate a concept for beam smoothing in high-energy laser systems.
• To reduce far-field nonuniformity by incoherently mixing multiple coherent beams.

Main Methods:

• Multiplexing multiple coherent beams to create an incoherent mix.
• Utilizing random spatial phase modulation via a phase plate.
• Combining spatial multiplexing with smoothing by spectral dispersion.

Main Results:

• Modeling confirmed effective scaling of smoothing with the number of uncorrelated beams.
• Experimental demonstration with up to six beams showed over 40 modes achieved.
• Results were consistent with theoretical expectations for reduced nonuniformity.

Conclusions:

• The demonstrated beam smoothing scheme offers practical advantages for high-energy laser systems.
• The technique effectively reduces far-field nonuniformity through incoherent beam mixing.
• Future developments could further enhance laser system performance and capabilities.