Infrared

What is INFRARED? Explains the principle,uses and application of INFRARED in daily life. Technology of INFRARED in various fields like medical, archaeology,astronomy and many others.

1. Ec 301 Computer networking fundamentals topic: infrared Presenters Tharshini elangovan 08deu13f2031 shaleni kavirajan 08deu13f2013 Lecturer Pn Fazida bt adlan

2. Origin of “INFRARED” The name means below red, the Latin infra meaning "below" . Red is the color of the longest wavelengths of visible light. Infrared light has a longer wavelength (and so a lower frequency) than that of red light visible to humans, hence the literal meaning of below red. INFRARED=INFRA+ RED

3. History of infrared DISCOVERY OF INFRARED - Sir Frederick William Herschel Showed that the Sun emits Infrared light by using a 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. He was surprised at the result and called them "Calorific Rays ". Calorific means “Heat generating.”

4. Where is infrared radiation found? Infrared waves are emitted by all warm objects. They also heat up the objects on which they fall. When they fall on any substances, the molecules in the substances absorb this energy and get excited and as a result of this, the substance gets heated. A very good example is the earth . Earth gets heated up, due to the infrared radiation falling on it from the Sun.

5. How does Infrared radiation work? Infrared radiation is heat radiated by an object. When an object gets heated, it gains energy as a result of which the atoms and molecules move or vibrate and radiate infrared which is heat. Objects that are not hot enough to radiate visible light will radiate infrared . When infrared waves touch a surface or fall on any substances / objects, heat energy is released. This heat energy is not dependent on the temperature of the surroundings . Examples of infrared radiation are, heat from the Sun , heat from fire , heat from radiator , etc . The energy from the Sun that reaches the earth has a higher percentage of infrared radiation Infrared rays travel through air and vacuum and they do not need a medium to travel through. They heat up any objects on which they fall and produce heat. For example surface of the earth, walls of the house, human body, etc .

6. DIFFERENT REGIONS WITHIN INFRARED The infrared radiation is spread across a band (spectrum) of wavelengths (0.75 micrometer to 1000 micrometers) and hence it is divided into smaller sections. Sensors are very sensitive and do not detect all of these wavelengths and they will be built to sense a particular / small band of wavelengths. So infrared radiation of each region has different use or application. The different divisions of the infrared region are as follows ;

7. The International Commission on Illumination has divided it into three general sections based on the length of the wave and density

8. Regions of INFRARED Characteristics Near INFRARED, NIR The wavelength range is from 0.75 to 1.4 micrometers. This is the region near to the visible red region. This is used in fibre optic communication and night vision devices. It is also used in remote controls, astronomy, remote monitoring, material science, medical field and agriculture. Short wavelength INFRARED, SWIR The wavelength range is from 1.4 to 3 micrometers. This is used for long distance telecommunications. It is also used in SWIR cameras, night vision goggles that play a major role for military purposes. Medium INFRARED, MIR The wavelength range is 3 to 8 micrometers. This is used in guided missile technology, infrared spectroscopy, communication, chemical industry, and astronomy.

9. Regions of INFRARED Characteristics Long wavelength INFRARED, LWIR The wavelength range of this division is 8 to 15 micrometers. This is the thermal infrared region and is used to detect thermal emissions that require no illumination from other sources (thermal imaging). This finds extensive application in astronomical telescopes and optical fibre communication Far INFRARED, FIR The wavelength range is 15 to 1000 micrometers. These are used in infrared lasers, astronomy, infrared saunas and extensively used in the medical field where it helps strengthen immune system such as cancer therapy.

10. Detection of Infrared radiation Infrared radiation can be detected by infrared detectors that react to infrared radiation Infrared imaging cameras are a good example for recording infrared images. There are some electronic devices that can detect infrared radiation and they have to be maintained at a lower temperature in order to avoid heat from the device interfering with the detection of infrared . For example; Thermocouple detectors, Bolometers - Heat sensitive devices that react to the presence of IR radiation Photovoltaic cells, photoconductors - made of semiconductor materials. The electrical conductivity of these materials increase when exposed to infrared radiation thereby helping with the detection of IR radiation

11. Uses of infrared

12. Applications of Infrared