Visible spectrum
hideThe visible spectrum is the portion of the electromagnetic spectrum that is visible to (can be detected by) the human eye. Electromagnetic radiation in this range of wavelengths is called visible light or simply light. A typical human eye will respond to wavelengths from about 380 to 750 nm. In terms of frequency, this corresponds to a band in the vicinity of 790–400 terahertz. A light-adapted eye generally has its maximum sensitivity at around 555 nm (540 THz), in the green region of the optical spectrum (see: luminosity function). The spectrum does not, however, contain all the colors that the human eyes and brain can distinguish. Unsaturated colors such as pink, and purple colors such as magenta are absent, for example, because they can only be made by a mix of multiple wavelengths.
Visible wavelengths also pass through the "optical window," the region of the electromagnetic spectrum that passes largely unattenuated through the Earth's atmosphere. (Blue light scatters more than red light, which is why the sky appears blue.) The human eye's response is defined by subjective testing (see CIE), but atmospheric windows are defined by physical measurement.
The "visible window" is so called because it overlaps the human visible response spectrum. The near infrared (NIR) windows lie just out of human response window, and the Medium Wavelength IR (MWIR) and Long Wavelength or Far Infrared (LWIR or FIR) are far beyond the human response region.
Many species can see wavelengths that fall outside the "visible spectrum". Bees and many other insects can see light in the ultraviolet, which helps them find nectar in flowers. Plant species that depend on insect pollination may owe reproductive success to their appearance in ultraviolet light, rather than how colorful they appear to us. Birds too can see into the ultraviolet (300-400 nm), and some have sex-dependent markings on their plumage, which are only visible in the ultraviolet range.
For more information about Visible spectrum, read the full article at
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News tagged with visible spectrum
Mantis shrimps could show us the way to a better DVD
Oct 25, 2009 |
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(PhysOrg.com) -- The remarkable eyes of a marine crustacean could inspire the next generation of DVD and CD players, according to a new study from the University of Bristol published today in Nature Photonics.
High in Sodium: Highly Charged Tungsten Ions May Diagnose Fusion Energy Reactors
Sep 08, 2009 |
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(PhysOrg.com) -- Just as health-food manufacturers work on developing the best possible sodium substitutes for low-salt diets, physicists at the National Institute of Standards and Technology have acquired ...
Trifid triple threat
Aug 26, 2009 |
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Smouldering several thousand light-years away in the constellation of Sagittarius (the Archer), the Trifid Nebula presents a compelling portrait of the early stages of a star's life, from gestation to first ...
UGA, UPR grant license for long-persistence glow materials, in any color
Aug 17, 2009 |
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The University of Georgia Research Foundation, Inc. (UGARF) and the University of Puerto Rico have granted an international, non-exclusive license for a portfolio of glow-in-the-dark pigments that can be designed ...
LED closes the yellow gap: Full conversion of blue into amber light by new nitride phosphor
Jul 23, 2009 |
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(PhysOrg.com) -- Monochromatic light-emitting diodes cover a large part of the visible spectrum with high effi-ciency. For blue light, nitride diodes achieve external quantum efficiencies in excess of 65%, ...
New 'broadband' cloaking technology simple to manufacture
May 20, 2009 |
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(PhysOrg.com) -- Researchers have created a new type of invisibility cloak that is simpler than previous designs and works for all colors of the visible spectrum, making it possible to cloak larger objects ...
Carbon nanotube device can detect colors of the rainbow
Nanotechnology / Nanomaterials
Apr 30, 2009 |
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Researchers at Sandia National Laboratories have created the first carbon nanotube device that can detect the entire visible spectrum of light, a feat that could soon allow scientists to probe single molecule ...
Discovery of an Unexpected Boost for Solar Water-Splitting Cells
Nanotechnology / Nanomaterials
Apr 22, 2009 |
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(PhysOrg.com) -- A research team from Northeastern University and the National Institute of Standards and Technology has discovered, serendipitously, that a residue of a process used to build arrays of titania ...
