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Red (635 nm), blueish violet (445 nm), and green (520 nm) laser pointers. A laser pointer or laser pen is a (typically battery-powered) handheld device that uses a laser diode to emit a narrow low-power visible laser beam (i.e. coherent light) to highlight something of interest with a small bright colored spot.
A blue or red laser will appear much dimmer—and thus less distracting—than a green or yellow laser of equal power. [8] For example, a 10-watt continuous-wave yttrium aluminium garnet laser at 532 nanometers (green) can appear brighter to the eye than an 18-watt continuous-wave argon-ion laser that outputs 10 watts of 514 nm (green-blue ...
A laser normally produces a very narrow beam of light in a single wavelength, in this case, green. Photons, the quanta of electromagnetic radiation, are released and absorbed from energy levels in atoms and molecules. In a lightbulb or a star, the energy is emitted from many different levels giving photons with a broad range of energies.
Mixing red, green, and blue sources to produce white light needs electronic circuits to control the blending of the colors. Since LEDs have slightly different emission patterns, the color balance may change depending on the angle of view, even if the RGB sources are in a single package, so RGB diodes are seldom used to produce white lighting.
The Nd:YAG laser is the most common laser used in laser designators and laser rangefinders. During the Iran–Iraq War, Iranian soldiers suffered more than 4000 cases of laser eye injury, caused by a variety of Iraqi sources including tank rangefinders. The 1064 nm wavelength of Nd:YAG is thought to be particularly dangerous, as it is invisible ...
The laser printer was invented at Xerox PARC in the 1970s. Laser printers were introduced for the office and then home markets in subsequent years by IBM, Canon, Xerox, Apple, Hewlett-Packard and many others. Over the decades, quality and speed have increased as prices have decreased, and the once cutting-edge printing devices are now ubiquitous.
While a DVD uses a 650 nm red laser, Blu-ray Disc uses a 405 nm blue laser diode. Although the laser is called blue, its color is actually in the violet range. The shorter wavelength can be focused to a smaller area, thus enabling it to read information recorded in pits that are less than half the size of those on a DVD, and can consequently be ...
This is an accepted version of this page This is the latest accepted revision, reviewed on 17 February 2025. Art and practice of creating images by recording light For other uses, see Photography (disambiguation). Photography of Sierra Nevada Photography is the art, application, and practice of creating images by recording light, either electronically by means of an image sensor, or chemically ...