Experimental demonstration of spatially coherent beam combining using optical parametric amplification

Area of Science:

• Nonlinear Optics
• Laser Physics
• Quantum Optics

Background:

• Coherent beam combining is crucial for achieving high-intensity lasers.
• Optical parametric amplification (OPA) offers a pathway for high-gain amplification.
• Scaling OPA systems to high energies requires advanced beam combining techniques.

Purpose of the Study:

• To demonstrate coherent beam combining using optical parametric amplification.
• To investigate the use of a random-phased multiple-beam array for pumping.
• To assess the feasibility of scaling to exa-watt level intensities.

Main Methods:

• Experimental demonstration of coherent beam combining via OPA.
• Utilizing a nonlinear crystal pumped by a random-phased multiple-beam array.
• Employing a motorized actuator for precise phase control in a two-beam experiment.
• Using a random phase plate to generate multiple random-phased beamlets for pump pulse.

Main Results:

• Spatially coherent signal beams were successfully obtained in both proof-of-principle and multiple-beam experiments.
• Far-field patterns confirmed the beam quality of the amplified signal and idler beams.
• The demonstrated technique shows potential for scaling OPA systems to high intensities.

Conclusions:

• Coherent beam combining via OPA with a random-phased pump array is experimentally validated.
• This method offers a viable route for achieving ultra-high intensity lasers (exa-watt level).
• Diffraction-limited beam quality can be maintained during the scaling process.