High-Accuracy Surface Topography Manufacturing for Continuous Phase Plates Using an Atmospheric Pressure Plasma Jet

Area of Science:

• Diffractive optics
• Laser systems engineering
• Plasma processing technology

Background:

• Continuous phase plates (CPPs) are critical for laser beam shaping in high-power systems.
• Manufacturing CPPs with high accuracy is challenging due to complex surface features.

Purpose of the Study:

• To present a high-accuracy and high-efficiency surface topography manufacturing method for CPPs.
• To investigate the potential of atmospheric pressure plasma jet (APPJ) for CPP fabrication.

Main Methods:

• Utilized an atmospheric pressure plasma jet (APPJ) system and studied its removal characteristics.
• Developed an optimized iterative algorithm incorporating dwell point matrix and fast Fourier transform (FFT) for dwell time calculation.
• Fabricated a 120 mm × 120 mm CPP surface topography.

Main Results:

• Achieved a 1326.2 nm peak-to-valley (PV) surface topography in four iteration steps.
• Obtained a residual figure error of 28.08 nm root mean square (RMS) between the designed and fabricated surfaces.
• Demonstrated an energy radius deviation of 11 μm at 90% encircled energy in the far-field distribution.

Conclusions:

• The APPJ approach offers a viable method for manufacturing complex surface topographies with high precision.
• The developed iterative algorithm enhances accuracy and efficiency in CPP fabrication.
• The fabricated CPP exhibits excellent optical performance suitable for high-power laser applications.