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Show Laser Glossary, Definitions & Explanations This Glossary shall provide general definitions for terms used on this website as well as give some background information on terms and topics used in show laser and entertainment industry.
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What is divergence?

Divergence describes the expansion of a laser beam over a long distance. The value is given in mrad (milliradiant), a unit to specify angles.

What is better, a high value or a small value of divergence?

The higher the divergence, the bigger the widening of the laser beam over a long distance. Thus, the laser beam becomes less visible and sharp graphics can hardly be displayed over long distances. This means that the smalles possible divergence makes the best show laser. The laser beams stay thin and crisp even over the longest distances.

What is the relation between beam divergence and beam diameter at aperture?

It is possible to reduce the beam divergence by optical means (lenses) to a certain extent. However, this means that the beam diameter at aperture increases. The larger the beam at aperture, the larger scanner mirrors are necessary, which leads to higher inertia and thus to reduced maximum possible scan speed. That's why it is always necessary to find a good balance between beam divergence and beam diameter:

Beam specs: Laser beam divergence vs. beam diameter

Can I calculate how the laser beam behaves after a certain distance?

Thanks to the Laserworld divergence calculator this is no problem. You will find this tool on following page:
Just specify the laser power, your desired distance, the divergence of the show laser and the beam diameter after optics. All values can be found in the manual of your laser projector.

More information on divergence

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