Source: Wikipedia

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The Concept of Laser Beam Quality

A laser beam is considered diffraction-limited when it can be focused to small spots with high precision, limited only by the inherent diffraction effects. This indicates that the beam quality is at its best.

Defining Ideal Beam Quality

Ideal beam quality refers to a laser beam that, when focused using a curved mirror, has the smallest possible beam divergence angle associated with a given beam radius. The concept of ideal beam quality is often linked to Gaussian beams, which have flat wavefronts at the beam waist and a Gaussian intensity profile, resulting in the minimum beam parameter product.

Factors Affecting Beam Quality

The beam quality of a laser can be influenced by intracavity distortions, such as those occurring in the gain medium, which may lead to non-ideal beam shapes or transverse multimode operation. Optimizing the resonator design of the laser is crucial for achieving diffraction-limited output.

Characterizing Beam Quality

For a given optical power, a diffraction-limited beam offers the highest brightness, or radiance. The M2 factor is a valuable metric for assessing how close a beam is to being diffraction-limited.

Conclusion

Understanding laser beam quality is essential for optimizing laser performance and achieving high-quality laser output. By considering factors such as beam divergence, beam radius, and resonator design, researchers and engineers can work towards enhancing the beam quality of laser systems.

Source: Wikipedia
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