infrared

the infrared region of the electromagnetic spectrum

electromagnetic wave frequencies below the visible range

"they could sense radiation in the infrared" electromagnetic radiation with wavelengths longer than visible light but shorter than radio waves having or employing wavelengths longer than light but shorter than radio waves

lying outside the visible spectrum at its red end

"infrared radiation"

"infrared photography"

Infrared (IR) radiation is electromagnetic radiation of a wavelength longer than that of visible light, but shorter than that of microwave radiation. The name means "below red" (from the Latin ''infra'', "below"), red being the color of visible light of longest wavelength. Infrared radiation spans three orders of magnitude and has wavelengths between 1 E-7 m700 Nanometrenm and 1 millimetremm.

Different regions in the infrared - IR is often subdivided into:

near infrared NIR, IR-A ''DIN'', !0.7–1.4 micrometre< bara>µm in wavelength, defined by the water absorption, and commonly used in fiber optic telecommunication because of low attenuation losses in the SiO₂ glass (silica) medium.

short wavelength IR SWIR, IR-B ''DIN'', 1.4–3 µm, water absorption increases significantly at 1450 nm

mid wavelength IR MWIR, IR-C ''DIN'', also intermediate-IR (IIR), 3–8 µm

long wavelength IR LWIR, IR-C ''DIN'', 8–15 µm)

far infrared FIR, 15–1000 µm However, these terms are not precise, and are used differently in various studies i.e. near (0.7–5 µm) / mid (5–30 µm) / long (30–1000 µm). Especially at the telecom-wavelengths the spectrum is further subdivided into individual bands, due to limitations of detectors, amplifiers and sources. Infrared radiation is often linked to heat, since objects at room temperature or above will spontaneous emissionemit radiation mostly concentrated in the mid-infrared band (see black body). The common nomenclature is justified by the different human response to this radiation (near infrared = the red you just cannot see, far IR = thermal radiation), other definitions follow different physical mechanisms (emission peaks, vs. bands, water absorption) and the newest follow technical reasons (The common silicon detectors are sensitive to about 1050 nm, while indium gallium antimonideInGaAs sensitivity starts around 950 nm and ends between 1700 and 2200 nm, depending on the specific configuration). Unfortunately the international standards for these specifications are not currently available.

Telecommunication bands in the infrared - Optical telecommunication in the near infrared is technically often separated to different frequency bands because of availability of light sources, transmitting /absorbing materials (fibers) and detectors.

O-band 1260–1360 nm

E-band 1360–1460 nm

S-band 1460–1530 nm

C-band 1530–1565 nm

L-band 1565–1625 nm

U-band 1625–1675 nm

The Earth as an infrared emitter - The Earth's surface absorbs visible radiation from the sun and re-emits much of the energy as infrared back to the atmosphere. Certain gases in the atmosphere, chiefly water vapor, but also carbon dioxide, methane, nitrous oxide, sulfur hexafluoride, and chlorofluorocarbons, absorb this infrared, and re-radiate it in all directions including back to Earth. Thus, the greenhouse effect, keeps the atmosphere and surface much warmer than if the infrared absorbers were absent from the atmosphere.

Applications -

Night vision - Infrared is used in night-vision equipment, when there is insufficient visible light to see an object. The radiation is detected and turned into an image on a screen, hotter objects showing up brighter, enabling the police and military to acquire thermally significant targets, such as human beings and automobiles. ''Also see Forward looking infrared''.Smoke is more transparent to infrared than to visible light, so fire fighters use infrared imaging equipment when working in smoke-filled areas.

Other imaging - In infrared photography, infrared filterinfrared filters are used to capture only the infrared spectrum. Digital cameras often use infrared blockerblockers. Cheaper digital cameras and some camera phones which do not have appropriate filters can "see" infrared, appearing as a bright white colour (try pointing a TV remote at your digital camera). This is especially pronounced when taking pictures of subjects near bright areas (such as near a lamp), where the resulting infrared interference can wash out the image.

Thermography - Infrared radiation can be used to remotely determine the temperature of objects (if the emissivity is known). This is termed thermography, or in the case of very hot objects in the NIR or visible it is termed pyrometry. Thermography (thermal imaging) is mainly used in military and industrial applications but the technology is reaching the public market in the form of infrared cameras on cars due to the massively reduced production costs.

Heating - Infrared radiation is used in Infrared saunas to heat the sauna's occupants and to remove ice from the wings of aircraft (de-icing).

Communications - IR data transmission is also employed in short-range communication among computer peripherals and personal digital assistants. These devices usually conform to standards published by Infrared Data AssociationIrDA, the Infrared Data Association. Remote controls and IrDA devices use infrared light-emitting diodes (LEDs) to emit infrared radiation which is focused by a plastic Lens (optics)lens into a narrow beam. The beam is modulationmodulated, i.e. switched on and off, to encode the data. The receiver uses a silicon photodiode to convert the infrared radiation to an electric Current (electricity)current. It responds only to the rapidly pulsing signal created by the transmitter, and filters out slowly changing infrared radiation from ambient light. Infrared communications are useful for indoor use in areas of high population density. IR does not penetrate walls and so does not interfere with other devices in adjoining rooms.Free space opticsFree space optical communication using infrared lasers can be a relatively inexpensive way to install a Gigabit/s communications link in urban areas, compared to the cost of burying fibre optic cable.Infrared lasers are used to provide the light for optical fibre communications systems. Infrared light with a wavelength around 1330 nm (best transmission) or 1550 nm (least dispersion) are the best choices for standard silica fibres.

Spectroscopy - Infrared radiation spectroscopy is the study of the composition of (usually) organic compounds, finding out a compound's structure and composition based on the percentage transmittance of IR radiation through a sample. Different frequencies are absorbed by different stretches and bends in the molecular bonds occurring inside the sample. Carbon dioxide, for example, has an absorption band at 4.2µm.

History - The discovery of infrared radiation is commonly ascribed to William Herschel, the astronomer in the early 19th century. Herschel used a Prism (optics)prism to refract light from the sun and detected the infrared, beyond the red part of the spectrum, through an increase in the temperature recorded on a thermometer.

See also -

Night vision

Infrared astronomy

Infrared photography

Infrared spectroscopy

Thermography

External links -

Journals -

sciencedirect.com - Infrared Physics and Technology (Elsevier) (last access June 2005).

Web sites -

!scienceofspectroscopy.info - Infrared Spectroscopy NASA ''Open Spectrum'' wiki site.

irda.org - IrDAOrganization that creates low cost infrared data interconnection standards.EMSpectrum Category:Electromagnetic !spectrumbg:Инф рачервено? !излъчванеca:Infraroig cs:Tepelné? zářenída:Infrarød !strålingde:Infrarotstrahlunge t:Infrapunakiirguses:Radiació n? infrarrojaeo:Infraruĝa !radiadofa:فروسرخfr:Infra rougegl:Radiación? !infravermellaio:Infreredaid:In framerahit:Radiazione? infrarossahe:תת אדוםlv:Infrasarkanais !starojumsnl:Infraroodja:赤外 線no:Infrarød? !strålingpl:Podczerwieńpt:Rad iação? !infravermelharu:Инфракр асное? !излучениеsl:Infrarde� �e? !valovanjefi:Infrapunasäteilys v:Infraröd? strålningvi:Hồng ngoạizh:红外线

PLACEBO ADDICT
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Monochromators and Spectrometers and Imaging Spectrographs
McPherson manufactures High Resolution and Vacuum Monochromators and Spectrometers and CCD equipped Imaging Spectrographs. We deliver systems for work in the Visible to the Infrared, Deep Ultraviolet, Vacuum, Extreme Ultraviolet and Soft X-ray. Complete easy to use systems include Fiber Accessories, Light Sources, Detectors, Data Acquisition, Software and Control. Integrated System Solutions for Phosphor Measurement, Plasma and Fusion Diagnostics, Raman Spectroscopy, Spectral Microscopy, Multispectral Calibration, Optical Deposition Monitoring, Goniometric Spectrophotometry, Multi Fiber Imaging, Remote Spectral Sensing, and Process Control.
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www.daveweisman.com
David Weisman, L.L.C. designs and manufactures gas & electric infrared heater/control packages, and infrared, hot air/convection & combinations ovens. Applications include: Preheat/boost, cure, dry, postheat/postcure solvent & water-based paint and powder coatings on products. Heating for conveyorized metal, plastic, wood, etc. parts and paper, film, foil and textile continuous webs. Small to medium sized conveyorized ovens and turn-key systems. Automated or batch processes.
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http://www.irinfo.org
IRINFO.ORG is a content-based web resource and on-line community dedicated to professionally promoting infrared thermography and related PPM, PdM and NDT technologies.
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Red Wave Technologies
Professional and intelligent nondestructive testing services utilizing infrared thermography, visual inspection and industrial photography.
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Daytronik Solutions
Daytronik Solutions, based in Pretoria, South Africa, are supliers of professional multichannel digital voice logging recorder solutions for call centres and control rooms (radios and telephones), digital voice recorders for meetings and personal use, night vision equipment, public address systems, intercoms and CCTV, electronic test equipment, surveillance equipment, uninterruptable power supplies and commputer products
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LASEROPTIK GmbH - High power laser optics and coatings
Laseroptik is a manufacturer of high power optics and coatings for lasers and for laser components and substrates
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Infrared Processing and Analysis Center (IPAC)
Performs large, data-intensive processing tasks for NASA's infrared astronomy program. Results available.
http://www.ipac.caltech.edu/

Infared Data Association - IrDA
International organization that creates and promotes interoperable, low cost infrared data interconnection standards that support a walk-up, point-to-point user model. The standards support a broad range of appliances, computing and communications devices.
http://www.irda.org/

NASA Infrared Telescope Facility Home Page
Hawaii.
http://irtf.ifa.hawaii.edu/