Influence of symmetry breaking on the inner core of a structured laser beam

Area of Science:

• Optics and Photonics
• Metrology and Measurement Science

Background:

• Structured laser beams (SLBs) utilize their inner core (IC) as a precise reference line for optical measurements.
• Beam symmetry is critical for IC straightness, but obstructions can disrupt this symmetry.

Purpose of the Study:

• To investigate the symmetry breaking of SLBs caused by obstructions.
• To quantify the resulting IC displacement over long distances (up to 140 m).
• To validate numerical simulation methods for predicting symmetry breaking.

Main Methods:

• Numerical simulations of SLB behavior with obstructions.
• Experimental validation of simulation results.
• Analysis of IC displacement in near and far zones relative to the obstruction.

Main Results:

• Significant IC displacements (over 2 mm) observed for obstructions in the near zone (approx. 1.9 m).
• Smaller displacements (up to 0.3 mm) found for obstructions in the far zone.
• Displacements are substantially larger than measurement noise levels.

Conclusions:

• Symmetry breaking is a critical factor limiting the accuracy of SLB-based alignment systems.
• Numerical simulations are a reliable and efficient tool for analyzing symmetry breaking, reducing the need for extensive physical testing.
• Understanding symmetry breaking is essential for designing robust SLB alignment systems and predicting necessary clear space.