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What is M²?
(Beam Quality Factor)
M² (Beam Quality Factor) is a dimensionless parameter used to describe the quality of a laser beam compared with an ideal Gaussian beam. It indicates how well a beam can be focused and how closely its propagation characteristics approach those of an ideal beam.
For an ideal Gaussian beam, M² = 1. Higher M² values indicate greater deviation from the ideal beam and generally poorer beam propagation and focusing performance.
HOW M² Works
M² quantifies how the size and divergence of a real laser beam compare with those of an ideal Gaussian beam. It provides a standardized way to characterize beam propagation and focusing performance.
Beam measurement
The beam width and divergence are measured at different positions along its propagation path.
Comparison with an ideal beam
These measurements are compared with the theoretical behavior of an ideal Gaussian beam to determine the M² factor.
Beam quality assessment
An M² value close to 1 indicates a high-quality beam with good focusing and propagation characteristics, while higher values indicate a more divergent or multimode beam.
