Infrared sources are optoelectronic devices that emit infrared light, electromagnetic radiation with wavelengths longer than visible light but shorter than radio waves. The infrared (IR) region of the electromagnetic spectrum is located between red light and radio frequency (RF) waves. Infrared radiation spans wavelengths between 750 nm and 1 mm and can be divided into five categories: near infrared (NIR), short wavelength infrared (SWIR), mid wavelength infrared (MWIR), long wavelength infrared (LWIR) and far infrared (FIR). Infrared sources vary in terms of capabilities and may emit infrared light in some or all of these infrared bands. For example, infrared sources that are designed for telecommunication applications may serve as an infrared light source for the 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), and U-band (1625 - 1675 nm).

There are three basic types of infrared sources: light emitting diodes (LEDs), thermal sources and tunable diodes. Light-emitting diodes (LED) are PN junction devices that give off light radiation when biased in the forward direction. Important performance specifications to consider when searching for light emitting diodes (LED) include LED type, peak wavelength, viewing angle, optical power output, luminous intensity, forward current, and forward voltage. Thermal sources contain a heat source that can deliver a heat flux, at a distinct temperature, into a sample. They are often combined with a calorimeter, a temperature-measuring device that can read the resultant change in temperature. Tunable diodes are infrared sources that can be adjusted to emit one of several different wavelengths.

Infrared sources are optoelectronic devices that emit infrared light, electromagnetic radiation with wavelengths longer than visible light but shorter than radio waves. The infrared (IR) region of the electromagnetic spectrum is located between red light and radio frequency (RF) waves. Infrared radiation spans wavelengths between 750 nm and 1 mm and can be divided into five categories: near infrared (NIR), short wavelength infrared (SWIR), mid wavelength infrared (MWIR), long wavelength infrared (LWIR) and far infrared (FIR). Infrared sources vary in terms of capabilities and may emit infrared light in some or all of these infrared bands. For example, infrared sources that are designed for telecommunication applications may serve as an infrared light source for the 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), and U-band (1625 - 1675 nm).

There are three basic types of infrared sources: light emitting diodes (LEDs), thermal sources and tunable diodes. Light-emitting diodes (LED) are PN junction devices that give off light radiation when biased in the forward direction. Important performance specifications to consider when searching for light emitting diodes (LED) include LED type, peak wavelength, viewing angle, optical power output, luminous intensity, forward current, and forward voltage. Thermal sources contain a heat source that can deliver a heat flux, at a distinct temperature, into a sample. They are often combined with a calorimeter, a temperature-measuring device that can read the resultant change in temperature. Tunable diodes are infrared sources that can be adjusted to emit one of several different wavelengths.

There are many applications for infrared sources. Infrared spectroscopy measures the amount of infrared radiation transmitted through a sample. Infrared thermography or thermal imaging can be used to determine the temperature of remote objects. An infrared lamp is an infrared light source that consists of a high-power incandescent lamp that emits infrared (IR) radiation. Personal digital assistants (PDA) that use IR data transmissions in short-range communication comply with standards published by the Infrared Data Association (IrDA).