Definition

1. Adjective:

   • Having or using electromagnetic radiation with wavelengths longer than those of visible red light but shorter than those of radio waves. This radiation is invisible to the human eye.
   • Relating to, producing, or using this type of radiation.

2. Noun (uncountable):

   • The part of the electromagnetic spectrum consisting of infrared radiation.
   • Infrared radiation itself.

Usage Examples

• Adjective:

  • Many security cameras use infrared light to see in the dark.
  • The scientist studied the object using an infrared telescope.
  • This material is designed to reflect infrared heat.

• Noun:

  • The remote control communicates with the television using infrared.
  • Snakes can detect the infrared emitted by warm-blooded prey.
  • Astronomers observe infrared from distant stars to learn about their composition.

Advanced Usage

• Infrared spectroscopy: An analytical technique that uses infrared light to identify molecules based on how they absorb specific wavelengths.
• Near-infrared (NIR) / Far-infrared (FIR): Subdivisions of the infrared spectrum based on wavelength, with different applications (e.g., NIR in fiber optics, FIR in thermal imaging).
• Passive vs. Active Infrared: Passive systems detect infrared naturally emitted by objects (like thermal cameras), while active systems emit infrared and detect its reflection (like some night-vision systems).

Variants and Related Words

• IR (abbreviation): A common abbreviation for infrared.
  • The device has an IR receiver.
• Thermal imaging / Thermography: A technology that creates images based on the infrared radiation (heat) emitted by objects.
• Infrared lamp: A lamp that emits infrared radiation, often used for therapeutic heating.

Synonyms

• Radiant heat (in specific contexts, as infrared is often perceived as heat).
• Thermal radiation (specifically for the longer-wavelength infrared associated with heat).

Related Phrases and Compounds

• Infrared sensor: A device that detects infrared radiation.
• Infrared spectrum: The range of wavelengths that constitute infrared radiation.
• Infrared astronomy: The branch of astronomy that observes and studies infrared radiation from celestial objects.

Adjective

1. 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

Noun

1. electromagnetic radiation with wavelengths longer than visible light but shorter than radio waves
2. the infrared region of the electromagnetic spectrum; electromagnetic wave frequencies below the visible range
   • they could sense radiation in the infrared