Refractive turbulence strength estimation based on the laser echo signal amplification effect.

Experimental data proving the possibility of lidar measurement of the refractive turbulence strength based on the effect of backscattering amplification are reported. It is shown, for the first time to our knowledge, that the values of the amplification factor correlate with the variance of random jitter of the optical image of an incoherent light source depending on the value of the structure constant of the air refractive index turbulent fluctuations averaged over the probing path.

Laser echo signal amplification in a turbulent atmosphere.

A lidar system for registration of laser return amplification in a turbulent atmosphere due to backscatter amplification effect is considered in this paper. In the system, two receiving channels are used. One of them (axial) coincides with the transmitter channel, while another channel (nonaxial) receives the backscattered radiation at a small angle to the probing beam axis.

Frequency locking to the center of a 532 nm iodine absorption line by using stimulated brillouin scattering from a single-mode fiber.

A simple method for frequency locking a frequency-doubled Nd:YAG laser to the center of line 1109 of the iodine absorption spectrum is described. The 31.6 GHz frequency shift provided by stimulated-Brillouin scattering from a single-mode silica fiber provides a probe signal that lies on the edge of line 1105 of the iodine spectrum.

Noise-proof inversion of lidar equation.

The reasons for instability of the lidar equation solution are investigated. An effective method of recovering the attenuation coefficient profile and transmittance of an optically thick atmosphere from the data of single-frequency laser sounding is suggested. The method enables one to obtain stable solutions of the lidar equation for sounding paths adjacent to the horizontal ones withoutthe use of absolute calibration of the lidar.