Near-diffraction-limited annular flattop beam shaping with dual phase only liquid crystal spatial light modulators

Area of Science:

• Optics and Photonics
• Laser Beam Shaping
• Spatial Light Modulation

Background:

• Conventional annular beam shaping techniques often alter the output beam's wavefront.
• Maintaining wavefront integrity is crucial for precise laser applications.
• Refractive laser beam shaping systems offer potential for advanced beam control.

Purpose of the Study:

• To demonstrate a novel annular flattop beam shaping technique.
• To maintain the wavefront of the output laser beam.
• To analyze the impact of beam parameter deviations on the output profile.

Main Methods:

• Utilized dual phase-only liquid crystal spatial light modulators (LC-SLMs).
• One LC-SLM redistributed the laser beam's intensity.
• A second LC-SLM restored the initial underlying wavefront.

Main Results:

• Achieved an annular flattop intensity distribution with high power containment (71% within <7% rms intensity variation).
• The output beam maintained a near-diffraction-limited quality with a 4.1mm diameter.
• The desired beam profile was sustained over a working distance exceeding 24cm in the near field.

Conclusions:

• The dual LC-SLM technique successfully generates annular flattop beams while preserving wavefront.
• This method offers superior control over beam profiles compared to conventional techniques.
• The technique is robust against certain beam parameter deviations, showing practical applicability.