Factors to Consider in Light Wave Transmission of Laser Camera

Absorption of molecules in the atmosphere

The signal loss of the atmospheric transmission system for LED and LD emission is mainly caused by the absorption of their transmission medium - the atmosphere. Because when a beam of light passes through a gas, there will always be a certain degree of molecular absorption. Moreover, air absorbs certain wavelengths of light particularly strongly, which cannot be used for signal transmission at all. The band where attenuation caused by atmospheric absorption is acceptable is called the atmospheric window. The data of this atmospheric transmission window band can be found in various literature, so all LED and LD systems must operate at the wavelength within this atmospheric transmission window.

Absorption of particles in the air

Particles in the air, such as dust and smoke, are another factor that causes absorption of light signals. Obviously, the atmosphere always contains some such particles to varying degrees, especially near water bodies, and the content of such particles is sometimes very high. In these places, it is generally advisable to install optical equipment as high as possible above the ground to improve the effectiveness of optical transmission

Absorption and scattering of fog

Mist is also a factor that causes severe infrared absorption, and it can also cause forward and backward scattering of light. Therefore, in foggy areas, the working hours of the optical transceiver equipment must be selected according to the local climate, as the system will not function properly when foggy.

The impact of atmospheric turbulence

The atmosphere has a certain degree of disorder, which not only causes signal loss, but also adds noise to the signal. Wind can cause atmospheric turbulence, which in turn can cause changes in the refractive index of air along the signal path. This phenomenon is similar to the occurrence of heat waves and mirages in areas exposed to sunlight. This effect will eventually refract the infrared beam to other directions that cannot be determined, making it impossible for the camera to capture the target being monitored.