Laser wave propagation through the atmosphere

Study on measurement uncertainty of laboratory calibration methods for transmissometer by numerical simulation

“…To get a high precision of calibration, it always choose a relative long baseline up to hundreds meters, which will suffer an affect by turbulence [11,12]. The beam wander, Angle-of-arrival [13], and scintillation [14] will cause the laser power overflowing from receiver.…”

Simulation of HF propagation and angle of arrival in a turbulent ionosphere

“…The irregular stratified ionosphere is assumed to lie above a free space region extending from z =-ZL (ground) to z = 0 (bottom of the ionosphere). The turbulent stratified ionosphere is then characterized by its relative permittivity oe(•) = <oe(z)> (1+ oe1(•)) The effect of depolarization is neglected, which is permissible when the wavelength is much smaller than the characteristic size of the irregularities [Hodara, 1966]. The same condition is required for the forward scattering assumption which will be used later.…”

Influence of Thermal Turbulence in a Convective Ascending Stream on Phase Fluctuations of a Laser Beam

“…As a matter of fact, the ratio L/8xt remains always much greater than one, so that ((A0 (DL/t) ]. (4) This expression is suitable for an experimental test on the dependence from the various parameters. They are the distance x from the grid, through the relation t = x/v(x), the separation d between the interfering 5.…”

“…3 As is well known, phase fluctuations of a laser beam propagating in atmosphere are affected by refractive index variations, which are mainly due to temperature random changes, the phenomenon usually termed as thermal turbulence. 4 This fact leads one to consider, as a very rough model for studying near earth propagation, the case in which turbulence is generated by the heating of the ground and then made to upstream by the convective motion. The relevance of such a model to real environmental conditions is strongly limited by the presence of wind, the effects of which cannot in general be neglected.…”