A laser beam quality definition based on induced temperature rise.

Area of Science:

• Optics and Photonics
• Laser Physics
• Materials Science

Background:

• Conventional laser beam quality metrics, such as M-squared, effectively describe ideal laser beams.
• These metrics can be inconsistent for non-ideal beams, particularly those with near-field diffraction or unusual profiles, leading to incomplete far-field performance descriptions.

Purpose of the Study:

• To motivate and define an alternative laser beam quality metric applicable to any beam profile.
• To address the limitations of conventional metrics in describing the far-field performance of non-ideal laser beams.

Main Methods:

• Developed a new beam quality definition based on the intrinsic material heating capability of a laser beam profile.
• Performed comparative analysis against conventional beam quality metrics.
• Analyzed an asymmetric Gaussian beam to connect the new metric with the invariant beam propagation ratio.

Main Results:

• The proposed metric offers a more consistent and complete description of laser beam quality, especially for complex or non-ideal beams.
• Established a link between the new material-heating-based metric and the established invariant beam propagation ratio.

Conclusions:

• The intrinsic material heating ability provides a robust and universally applicable definition for laser beam quality.
• This alternative metric enhances the characterization of laser beam propagation and far-field performance.