*Article* **Real-Time Correction of a Laser Beam Wavefront Distorted by an Artificial Turbulent Heated Airflow**

**Alexey Rukosuev \*, Alexander Nikitin, Vladimir Toporovsky , Julia Sheldakova and Alexis Kudryashov**

Institute of Geosphere Dynamics (IDG RAS), 119334 Moscow, Russia; nikitin@activeoptics.ru (A.N.); topor@activeoptics.ru (V.T.); sheldakova@nightn.ru (J.S.); kud@activeoptics.ru (A.K.) **\*** Correspondence: alru@nightn.ru

**Abstract:** This paper presents a FPGA-based closed-loop adaptive optical system with a bimorph deformable mirror for correction of the phase perturbation caused by artificial turbulence. The system's operating frequency of about 2000 Hz is, in many cases, sufficient to provide the real-time mode. The results of the correction of the wavefront of laser radiation distorted by the airflow formed in the laboratory conditions with the help of a fan heater are presented. For detailed consideration, the expansion of the wavefront by Zernike polynomials is used with further statistical analysis based on the discrete Fourier transform. The result of the work is an estimation of the correction efficiency of the wavefront distorted by the turbulent phase fluctuations. The ability of the bimorph adaptive mirror to correct for certain aberrations is also determined. As a result, it was concluded that the adaptive bimorph mirrors, together with a fast adaptive optical system based on FPGA, can be used to compensate wavefront distortions caused by atmospheric turbulence in the real-time mode.

**Keywords:** adaptive optics; bimorph mirror; fast adaptive optical system; turbulence; wavefront sensor; Zernike polynomials; spectral analysis
