Laser lighting display

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A laser show is a live multimedia performance. Classical spectacular laser effects.jpg
A laser show is a live multimedia performance.
Copper vapor laser in operation. Seen in South Florida in February 2006. CopperBromideLaser.jpg
Copper vapor laser in operation. Seen in South Florida in February 2006.
Muse on stage at Outside Lands Music and Arts Festival in San Francisco, 13 August 2011 Muse at Outside Lands Music and Arts Festival 03.jpg
Muse on stage at Outside Lands Music and Arts Festival in San Francisco, 13 August 2011
Multimedia Laser Show in Beach Club on board of AIDAPrima Multimedia Laser Show in Beach Club.png
Multimedia Laser Show in Beach Club on board of AIDAPrima

A laser lighting display or laser light show involves the use of laser light to entertain an audience. A laser light show may consist only of projected laser beams set to music, or may accompany another form of entertainment, typically musical performances.

Contents

Laser light is useful in entertainment because the coherent nature of laser light allows a narrow beam to be produced, which allows the use of optical scanning to draw patterns or images on walls, ceilings or other surfaces including theatrical smoke and fog without refocusing for the differences in distance, as is common with video projection. This inherently more focused beam is also extremely visible, and is often used as an effect. Sometimes the beams are "bounced" to different positions with mirrors to create laser sculptures. [1]

Function

Scanning

Laser scanners reflect the laser beam on small mirrors which are mounted on galvanometers 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 figures (such as are often displayed on oscilloscopes); other methods of creating images through the use of galvanometer scanners and X-Y 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 grating splits the monochromatic light into several rays, and by using holograms, essentially complicated gratings, the beam can be split into various patterns. [2] [3]

Diffraction uses something referred to as the 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. [4] 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. [5]

Safety

Some lasers have the potential to cause eye damage if aimed directly into the eye, or if someone were to stare directly into a stationary laser beam. Some high-power lasers used in entertainment applications can also cause burns or skin damage if enough energy is directed onto the human body and at a close enough range. In the United States, the use of lasers in entertainment, like other laser products, is regulated by the Food and Drug Administration (FDA) and additionally by some state regulatory agencies such as New York State which requires licensure of some laser operators. Safety precautions used by laser lighting professionals include beamstops and procedures so that the beam is projected above the heads of the audience. It is possible, and in some countries commonplace, to do deliberate audience scanning. In such a case, the show is supposed to be designed and analyzed to keep the beam moving, so that no harmful amount of laser energy is ever received by any individual audience member.

Lasers used outdoors can pose a risk of "flash blindness" to pilots of aircraft [6] if too-bright light enters the cockpit. In the U.S., outdoor laser use is jointly regulated by the FDA and the Federal Aviation Administration. For details, see the article Lasers and aviation safety. In Europe the standard EN60825 is the reference concerning the conformity of the equipments of every laser-sources-production industries.

Maximum Permissible Exposure (MPE) is the maximum amount of visible laser radiation considered not to cause harm, for a given exposure time. In many European countries these exposure limits may also be a legal requirement. The MPE is 25.4W/m2 for a period of 250 milliseconds, which is equivalent to 1mW over 7mm circular aperture (the size of the human pupil). [7]

History

One of the pioneers in the use of lasers in multimedia productions was the Polish-Australian artist Joseph Stanislaus Ostoja-Kotkowski, whose explorations of their artistic possibilities at Stanford University, California, and later at the Weapons Research Establishment at Salisbury, South Australia led to his innovative 'Sound and Image' show at the 1968 Adelaide Festival of Arts. [8]

Laser light shows fully emerged in the early 1970s and became a form of psychedelic entertainment, usually accompanied with a live musical performance on stage or pre-recorded music. The Who, Pink Floyd, Led Zeppelin, Genesis, and Electric Light Orchestra were among the first high-profile rock acts to use lasers in their concert shows in the mid-1970s. [9] Blue Öyster Cult used laser shows on tours that supported their album Spectres , which shows a staged portrait of the band members seated among the laser beams, and Electric Light Orchestra made use of lasers during their 1978 Out of the Blue Tour which also featured the famous "Flying Saucer". This is now highly regulated in the U.S., to the point where almost no U.S. shows have laser beams that go into or close to the audience. [10]

During the social distancing phase of the COVID-19 pandemic, some drive-in theaters offered laser shows. One company managed over 400 laser shows at locations around the United States by August 2021. [11]

See also

Related Research Articles

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A galvanometer is an electromechanical measuring instrument for electric current. Early galvanometers were uncalibrated, but improved versions, called ammeters, were calibrated and could measure the flow of current more precisely.

Holography Recording to reproduce a three-dimensional light field

Holography is a technique that enables a wavefront to be recorded and later re-constructed. Holography is best known as a method of generating three-dimensional images, but it also has a wide range of other applications. In principle, it is possible to make a hologram for any type of wave.

Barcode reader Electronic device

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Monochromator Optical device

A monochromator is an optical device that transmits a mechanically selectable narrow band of wavelengths of light or other radiation chosen from a wider range of wavelengths available at the input. The name is from the Greek roots mono-, "single", and chroma, "colour", and the Latin suffix -ator, denoting an agent.

In optics, the Fraunhofer diffraction equation is used to model the diffraction of waves when the diffraction pattern is viewed at a long distance from the diffracting object, and also when it is viewed at the focal plane of an imaging lens. In contrast, the diffraction pattern created near the object is given by the Fresnel diffraction equation.

Laser safety Protocols for safe use, design and implementation of laser technology

Laser radiation safety is the safe design, use and implementation of lasers to minimize the risk of laser accidents, especially those involving eye injuries. Since even relatively small amounts of laser light can lead to permanent eye injuries, the sale and usage of lasers is typically subject to government regulations.

The grating light valve (GLV) is a "micro projection" technology which operates using a dynamically adjustable diffraction grating. It competes with other light valve technologies such as Digital Light Processing (DLP) and liquid crystal on silicon (LCoS) for implementation in video projector devices such as rear-projection televisions. The use of microelectromechanical systems (MEMS) in optical applications, which is known as optical MEMS or micro-opto-electro-mechanical structures (MOEMS), has enabled the possibility to combine the mechanical, electrical and optical components in very small scale.

Audience scanning

Audience scanning occurs when a laser beam is directed toward the people observing a laser show or display. Although this is preferred for many laser effects such as tunnels, it is potentially dangerous due to the high levels of laser radiation exposed to the eyes of audience members.

Apodization

In signal processing, apodization is the modification of the shape of a mathematical function. The function may represent an electrical signal, an optical transmission or a mechanical structure. In optics, it is primarily used to remove Airy disks caused by diffraction around an intensity peak, improving the focus.

Laser scanning is the controlled deflection of laser beams, visible or invisible. Scanned laser beams are used in some 3-D printers, in rapid prototyping, in machines for material processing, in laser engraving machines, in ophthalmological laser systems for the treatment of presbyopia, in confocal microscopy, in laser printers, in laser shows, in Laser TV, and in barcode scanners.

Interference lithography is a technique for patterning regular arrays of fine features, without the use of complex optical systems or photomasks.

Joseph Stanislaus Ostoja-Kotkowski

Joseph Stanislaus Ostoja-Kotkowski AM, FRSA was best known for his ground-breaking work in chromasonics, laser kinetics and 'sound and image' productions. He earned recognition in Australia and overseas for his pioneering work in laser sound and image technology. His work included painting, photography, film-making, theatre design, fabric design, murals, kinetic and static sculpture, stained glass, vitreous enamel murals, op-collages, computer graphics, and laser art. Ostoja flourished between 1940 and 1994.

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Laser beam profiler

A laser beam profiler captures, displays, and records the spatial intensity profile of a laser beam at a particular plane transverse to the beam propagation path. Since there are many types of lasers — ultraviolet, visible, infrared, continuous wave, pulsed, high-power, low-power — there is an assortment of instrumentation for measuring laser beam profiles. No single laser beam profiler can handle every power level, pulse duration, repetition rate, wavelength, and beam size.

Laser projector

A laser projector is a device that projects changing laser beams on a screen to create a moving image for entertainment or professional use. It consists of a housing that contains lasers, mirrors, galvanometer scanners, and other optical components. A laser projector can contain one laser light source for single-color projection or three sources for RGB full color projection.

An electronic visual display, informally a screen, is a display device for presentation of images, text, or video transmitted electronically, without producing a permanent record. Electronic visual displays include television sets, computer monitors, and digital signage. By the above definition, an overhead projector could reasonably be considered an electronic visual display since it is a display device for the presentation of an images, plain text, or video transmitted electronically without producing a permanent record. They are also ubiquitous in mobile computing applications like tablet computers, smartphones, and information appliances.

Microscanner

A microscanner, or micro scanning mirror, is a microoptoelectromechanical system (MOEMS) in the category of micromirror actuators for dynamic light modulation. Depending upon the type of microscanner, the modulatory movement of a single mirror can be either translatory or rotational, on one or two axes. In the first case, a phase shifting effect takes place. In the second case, the incident light wave is deflected.

A common-path interferometer is a class of interferometers in which the reference beam and sample beams travel along the same path. Examples include the Sagnac interferometer, Zernike phase-contrast interferometer, and the point diffraction interferometer. A common-path interferometer is generally more robust to environmental vibrations than a "double-path interferometer" such as the Michelson interferometer or the Mach–Zehnder interferometer. Although travelling along the same path, the reference and sample beams may travel along opposite directions, or they may travel along the same direction but with the same or different polarization.

Vernier spectroscopy is a type of cavity enhanced laser absorption spectroscopy that is especially sensitive to trace gases. The method uses a frequency comb laser combined with a high finesse optical cavity to produce an absorption spectrum in a highly parallel manner. The method is also capable of detecting trace gases in very low concentration due to the enhancement effect of the optical resonator on the effective optical path length.

References

  1. ↑ "Laser Sculpture". Cape Lasers. Retrieved 6 May 2015.
  2. ↑ "GALAXY 3D LASER LIGHT SHOW". Galaxy3d.org. Retrieved 2012-02-07.
  3. ↑ "Movie of consumer-grade diffraction based laser display". YouTube . Archived from the original on 2021-12-12. Retrieved 2013-04-11.
  4. ↑ "Boundless Physics". Boundless Physics. 14 November 2016. Retrieved 14 November 2016.
  5. ↑ "Brief History of Laser Light Shows". Laser FX. Retrieved 6 May 2015.
  6. ↑ Safety, United States Air Mobility Command Chief of; Safety, United States Air Mobility Command Director of (1995). The Mobility forum: the journal of the Air Mobility Command. Chief of Safety, Air Mobility Command.
  7. ↑ "Laser safety: 10 tips | Kvant Laser Systems". Archived from the original on 2015-08-18. Retrieved 2014-11-13.
  8. ↑ June Edwards (2018), Ostoja-Kotkowski, Joseph Stanislaw (Stan) (1922–1994) , Australian Dictionary of Biography, National Centre of Biography, Australian National University. Retrieved 8 December 2019.
  9. ↑ "Strung Out On Lasers". tpimagazine.com. 2010-02-01. Archived from the original on 2013-04-10. Retrieved 2013-03-04.
  10. ↑ "Laser Light Show Safety - Who's Responsible?" (PDF). fda.gov. 1986-05-01. Retrieved 2013-03-04.
  11. ↑ Powell, Lisa (2021-08-16). "'Millions of diamonds in the sky': 1,000 laser beams will dazzle at drive-in show". Dayton.com. Retrieved 2021-10-03.
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