Far infrared

Overview

Diagram of the electromagnetic spectrum highlighting the far infrared region.

Far infrared (FIR) refers to the part of the electromagnetic spectrum that lies between the mid-infrared and the microwave regions. It encompasses wavelengths from approximately 15 micrometers (µm) to 1 millimeter (mm), corresponding to frequencies from about 20 terahertz (THz) to 300 gigahertz (GHz).

Characteristics

Far infrared radiation is characterized by its longer wavelengths compared to near infrared and mid-infrared radiation. This region of the spectrum is often associated with thermal radiation, as it is emitted by objects at room temperature and above. FIR is less energetic than visible light and is not visible to the human eye.

Applications

The far infrared region is used in various applications, including thermal imaging.

Far infrared radiation has a variety of applications in different fields:

• Thermal Imaging: FIR is used in thermal imaging cameras to detect heat emitted by objects, which is useful in night vision, surveillance, and firefighting.
• Medical Therapy: FIR is used in infrared saunas and other therapeutic devices to promote healing and relaxation by penetrating the skin and warming the body.
• Astronomy: In astronomy, FIR is used to observe cold and distant objects in space, such as interstellar dust and molecular clouds.
• Spectroscopy: FIR spectroscopy is used to study the vibrational and rotational transitions of molecules, providing insights into molecular structure and dynamics.

Biological Effects

Far infrared radiation is generally considered safe for humans, as it does not have the ionizing effects associated with higher energy radiation like ultraviolet or X-rays. However, prolonged exposure to intense FIR can cause thermal damage to tissues.

Related Pages

• Electromagnetic spectrum
• Infrared
• Thermal radiation
• Infrared spectroscopy
• Infrared sauna