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There are machines that are used to draw a line with light, for example to show workers a line along which they should cut something. I have also seen an artistic installation where clouds of artificial smoke are illuminated with planes of light, thus creating beautiful sheets of light.

How do such machines work?

My first thought was that the machine contains a laser beam, that is oscillating in rotational manner, with an axis of rotation that is perpendicular to the direction of the beam. Is this approach too naive? Are there better ways to do it?

PS: I'm not sure this is the proper SE website to ask my question. If not, could you suggest me a better one?

Fred
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Plop
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1 Answers1

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Your description and your understanding is on the mark. The laser beam creates a point of light, which when shone through a substance such as fog, appears as a straight line. A typical laser light show device consists of one or more lasers with the beams directed at front surface mirrors which are mounted in such a manner as to be manipulated by motors, sometimes piezo devices.

Persistence of vision (POV) in a human eye/brain allows the rapidly moving mirror and resultant light beam to appear as more than a dot and more than a line.

The engineering involved in such a machine secures your question in this SE. Popular Mechanics magazine has an article involving building a simplistic version using a 3D printer. In the case of this specific laser light show, the "motor" is a human being turning a crank which causes a cam to displace the laser, creating the POV image on a surface:

home made laser light show At the linked site, the image is an animated GIF.

fred_dot_u
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  • atleast some of the line lasers i have use some difraction grating to create a line. – joojaa May 09 '23 at 14:33
  • I have a few line lasers that use either a plastic or glass diffraction grating (better quality line with glass) but they are unsuitable for POV presentations. I overlooked the very first sentence, which your comment addresses quite appropriately. – fred_dot_u May 09 '23 at 15:09