Related topics: light · infrared light

Light-trapping nanocubes drive inexpensive multispectral camera

Researchers at Duke University have demonstrated photodetectors that could span an unprecedented range of light frequencies by using on-chip spectral filters created by tailored electromagnetic materials. The combination ...

New 3-D printing technique produces 'living' 4-D materials

Repairing and reusing plastics and delivering cancer drugs more effectively are only two of many of the potential applications a new 3-D/4-D printing technology might have, thanks to the pioneering work of a research collaboration ...

Protein imaging at the speed of life

To study the swiftness of biology—the protein chemistry behind every life function—scientists need to see molecules changing and interacting in unimaginably rapid time increments—trillionths of a second or shorter.

Researchers capture moving object with ghost imaging

Researchers have developed a way to capture moving objects with the unconventional imaging method known as ghost imaging. The new method could make the imaging technique practical for new applications such as biomedical imaging, ...

Pinpointing biomolecules with nanometer accuracy

It would be impossible to understand life without having a firm grasp on the microscopic interactions between molecules that occur in and around cells. Microscopes are and have been an invaluable tool for researchers in this ...

Harnessing plasmonics for precision agriculture worldwide

Maiken Mikkelsen wants to change the world by developing a small, inexpensive hyperspectral camera to enable worldwide precision farming practices that would significantly reduce water, energy, fertilizer and pesticide use ...

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Visible spectrum

The 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.

This text uses material from Wikipedia, licensed under CC BY-SA