Time-resolved measurements of the phase fluctuations of a coherent beam at the emergence from a turbulent layer

Si presenta un metodo, basato sull'uso dell'interferometro Ronchi, detto "Ronchi test", per misurare le fluttuazioni di fase, in differenti punti di un fronte d'onda laser, prodotte dalla turbolenza dopo un percorso nell'atmosfera. Si è fatto un esperimento e misurate correttamente fluttuazioni oltre "pi greco". We present a method, based on a interferometric Ronchi test to measure the phase fluctuations on a laser wavefront after a path through the atmospheric turbulence. The method has a good stability and allows one to measure fluctuations larger than "pi greek". To test the method, an experiment was set up and the fluctuations measured after a few meter path in the atmosphere with good results.