Custom Infrared Lens, thermal imaging cameras & systems components

What is an atmospheric window?
Atmospheric
window fefers to some bands of celestial radiation that can penetrate the
atmosphere. Due to the absorption and reflection of radiation by various
particles in the earth's atmosphere, only radiation from celestial bodies in
certain wavebands can reach the ground. Divided into optical window, infrared
window and radio window according to their respective scopes.
Infrared
window
Water vapor
molecules are the main absorbers of infrared radiation. Strong water vapor
absorption bands are located at 0.71~0.735μ (micron), 0.81~0.84μ, 0.89~0.99μ, 1.07~1.20μ, 1.3~1.5μ, 1.7~2.0μ, 2.4~3.3μ, 4.8~8.0μ. An absorption band of carbon dioxide
appears at 13.5~17μ.
The gaps between these absorption bands form some infrared windows. The widest
infrared window is at 8-13μ (there is an absorption band of ozone near 9.5μ).
17~22μ are
translucent windows. After 22μ until the wavelength of 1 millimeter, due to the
severe absorption of water vapor, it is completely opaque to observers on the
ground. But in places with high altitude and dry air, the radiation
transmittance of 24.5~42μ
can reach 30~60%.
At 3.5 kilometers above sea level, radiation of 330-380μ, 420-490μ, 580-670μ (transmittance of about
30%) can be observed, and 670-780μ (about 70%) and 800-910μ (about 30%) can be
observed. 85%) radiation.