بررسي ضريب تضعيف نور ليزر در نمونه آب هاي مختلف

Attenuation coefficient of laser beams In different types of water

The study of light propagation in seawater has improved in recent years. Among the newest methods is Laser Remote Sensing that gives us data from different sea layers in a, fraction of a second with no disturbance in the environment. In order to study the laser propagation in seawater, a series of experiments were performed by the second harmonic of Nd: YAG laser in the solid-state laser laboratory at the Atomic Energy Organi_ation of Iran. Using a mirror on the bed of a channel, we measured the reflected pulses by an energy-meter in different types of water (distilled water, drinking water, and a sample of water from the Oman Sea (60ʹ,30"E and 25ʹ,14"N) from a depth of 6 meters in Chabahar Ba)). Diagrams show that propagation of the laser light in water is nonlinear in different depths and intensities, and that it penetrates to a certain depth in constant intensity. As expected, higher radiant intensities had higher reflected intensity but a lower attenuation coefficient except in some points (contrary to the Beer ʹs law). The attenuation coefficient is bigger for the sample of the Oman Sea than the distilled water (in constant radiant intensity and angle) of which one of the reasons can be the dissolved material, determined by their salinity. So we can get information about the different types of water at different depths doing in situ experiments in a short time.