The order of infrared waves, from shortest to longest wavelength, is as follows:
Near-infrared (NIR): This region of the infrared spectrum has the shortest wavelengths and ranges from approximately 700 nanometers (nm) to 1.4 micrometers (µm). Near-infrared radiation is often used in optical communication, remote controls, and some medical applications.
Short-wavelength infrared (SWIR): Also known as mid-infrared, this region spans from about 1.4 µm to 3 µm. SWIR is used in various applications such as thermal imaging, spectroscopy, and surveillance.
Mid-wavelength infrared (MWIR): The MWIR region ranges from approximately 3 µm to 8 µm. It is commonly utilized in military and defense applications, such as target acquisition, missile tracking, and thermal imaging.
Long-wavelength infrared (LWIR): The LWIR region extends from around 8 µm to 15 µm. It is often employed in thermal imaging, night vision devices, and detecting heat signatures.
Far-infrared (FIR): This region has the longest wavelengths and starts around 15 µm, extending beyond the range of human vision. FIR radiation is often used in astronomy, thermal imaging, and industrial processes.
It's important to note that the specific wavelength ranges for each category may vary depending on the source and context.