Experimental investigation of an active open optical resonator in a turbulent atmosphere

The spectral densities of the time fluctuations of the amplitude of steady-state generation at two wavelengths ₁=0.63 and ₂=1.15 under conditions of turbulent fluctuations of the refractive index in the waveguide channel of an open optical resonator are studied. The frequency dependences of the spectral densities are analyzed at various states of atmospheric turbulence, including the state produced in an aerodynamic chamber. For wavelength ₂ the fluctuations of the water-vapor content form a random absorption field. The distinctive features of the frequency dependence of the spectral density are discussed and related to the time cross-correlation of random fields of the passive impurity of the water-vapor concentration, the temperature, and the turbulent velocity of the flow. The asymptotic behavior of the frequency dependences of the spectral density is analyzed from the standpoint of the self-similarity of the stochastic characteristics of the system consisting of the waveguide channel and the medium.Odessa Hydrometeorological Institute. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 34, No. 2, pp. 111–118, February, 1991.