Editing Laser lighting display (section)

== Function ==

=== Scanning ===
Laser scanners reflect the laser beam on small mirrors which are mounted on [[galvanometer]]s to which a control voltage is applied.  The beam is deflected a certain amount which correlates to the amount of voltage applied to the galvanometer scanner.  Two galvanometer scanners can enable X-Y control voltages to aim the beam to any point on a square. This is called vector scanning.  This enables the laser lighting designer to create  patterns such as [[Lissajous curve|Lissajous figures]] (such as are often displayed on [[oscilloscope]]s); other methods of creating images through the use of galvanometer scanners and X-Y-Z control voltages can generate letters, shapes, and even complicated and intricate images.  A planar or conical moving beam aimed through atmospheric smoke or fog can display a plane or cone of light known as a "laser tunnel" effect.

=== Diffraction ===
A less complicated way of spreading the laser beam is by means of [[diffraction]]. A [[diffraction grating|grating]] splits the [[monochromatic]] light into several rays, and by using [[hologram]]s, essentially complicated gratings, the beam can be split into various patterns.<ref>{{cite web|url=http://www.galaxy3d.org/ |title=GALAXY 3D LASER LIGHT SHOW |publisher=Galaxy3d.org |access-date=2012-02-07}}</ref><ref>{{cite web|url=https://www.youtube.com/watch?v=h4I4uF5w9u8  |archive-url=https://ghostarchive.org/varchive/youtube/20211212/h4I4uF5w9u8| archive-date=2021-12-12 |url-status=live|title=Movie of consumer-grade diffraction based laser display |website=[[YouTube]]|access-date=2013-04-11}}{{cbignore}}</ref>

Diffraction uses something referred to as the [[Huygens–Fresnel principle|Huygens-Fresnel principle]]. The basic idea is that on every wavefront exists a forward propagating spherical wavelet of light.  The initial wavefront manifests itself in the form of a straight line, as if the subject was seeing a wave coming in towards themselves in the water.  Aspects of the spherical waves that divert sideways are cancelled with the sideways components of the wave points on each respect point on either side. Diffraction is the primary method that many simple laser projectors work.<ref>{{Cite web|url=https://www.boundless.com/physics/textbooks/boundless-physics-textbook/wave-optics-26/diffraction-175/huygens-principle-636-5593/|title=Boundless Physics|date=14 November 2016|website=Boundless Physics|access-date=14 November 2016}}</ref>  Light is projected out towards multiple points.

=== Static beams ===
Uninterrupted stationary beams from one or more laser emitters are used to create aerial beam effects, which are turned on and off at varying intervals to create a sense of excitement. As the laser beam is not manipulated in any way, this could be considered the simplest form of a laser light show and also the least dynamic. Although this method is not as commonly used today due to the availability of scanners, these shows were precursors to laser light shows.<ref>{{cite web|title=Brief History of Laser Light Shows|url=http://www.laserfx.com/Backstage.LaserFX.com/Newsletter/BriefHistory.html|website=Laser FX|access-date=6 May 2015}}</ref>