Remote sensing of atmospheric turbulence profiles by laser guide stars

Remote sensing of ranged-resolved profiles of atmospheric turbulence is necessary and important for many applications in astronomical and adaptive optics communities. In order to obtain turbulence profiles in atmospheric boundary layer, a device is developed and experiments has been carried out. In the experiments, laser guide stars are formed at several successive altitudes by projecting pulsed laser, returned signals are received by two receiving telescopes and the images of the returned signals are formed by a imaging device. Variance of centroids′ distance is derived from the images with two spots at the same altitude and ranged-resolved profile of the variance is obtained. So, based on a inversion algorithm, atmospheric turbulence profiles are retrieved from differential image motion variance of distance of centroids at various altitudes. The structure constants of refractive index of atmosphere range from 10-14m-2/3 at lower altitudes to 10-16m-2/3 at higher altitudes are remote sensed experimentally. The results show it is a effective method that combined laser guide stars with differential image motion method and could sense atmospheric turbulence profiles remotely in real time.