R.S. Kuzin1, S.A. Buiko2, R.S. Kuzin3, A.V. Larichev4, S.V. Markin5

1–3,5 FSUE RFNC VNIIEF (Sarov, Russia)

1 The Faculty of Lomonosov Moscow State University (Sarov, Russia)

1,4 Lomonosov Moscow State University (Moscow, Russia)

1 roskuzin@vniief.ru, 4 larichev@optics.ru

The presence of inhomogeneities of the refractive index in the atmosphere under certain conditions leads to a negative impact on the operation of optical means. Therefore, it is often necessary to measure the strength of atmospheric turbulence in places where optical instruments are used, taking into account their characteristics. As part of the research, measurements of the value of the Fried parameter r0, characterizing the strength of optical turbulence, were carried out over a horizontal concreted surface and over the sea surface. A Shaka-Hartmann wavefront sensor was used as a point source image jitter meter. The measurement of the value r0 was performed by calculating the variance of the difference of the dot LED images on the video camera matrix. The measurements were carried out on horizontal tracks up to 200 meters long. The analysis of the obtained results is carried out. Keywords: laser, Fried parameter, turbulence, atmosphere, DIMM method, Shaka-Hartmann sensor, lens raster. In the work, pilot studies of the Frida parameter were conducted over water and land surfaces on routes of 100 and 200 meters. A battery-powered LED was used as the source, and a Shaka-Hartmann wavefront sensor with a telescope was used as the receiving system. It has been experimentally shown that the value of the Fried parameter r0pl above water exceeds approximately 2 times the parameter measured above the concrete surface under the same conditions, and the standard deviation of the Fried parameter above water exceeds this parameter above the concrete surface by more than 3 times. Long-term measurements of the Fried parameter r0pl above water indicate a change in the parameter over a wide range over time. During 30 minutes of continuous measurements, the value of r0pl varied in the range from 1 to 3 cm, and these changes are smooth with a characteristic change time of about 15 minutes.

Kuzin R.S., Buiko S.A., Kuzin R.S., Larichev A.V., Markin S.V. Measurement of atmospheric turbulence on a horizontal track over water. Electromagnetic waves and electronic systems. 2026. V. 31. № 1. P. 5−13. DOI: https://doi.org/10.18127/j15604128-202601-01 (in Russian)

1. Bolbasova L.A., Gritsuta A.N., Kopylov E.A., Lavrinov V.V., Lukin V.P., Selin A.A., Soin E.L. Atmospheric turbulence meter based on a Shack-Hartmann wavefront sensor. Journal of Optical Technology. 2019. V. 86. № 7. P. 426–430. DOI 10.1364/JOT.86.000426.
2. Troitskiy A.I. Optical links availability, taking into account effects of turbulent atmosphere. Radiotekhnika. 2008. № 2. P. 59–60. (in Russian)
3. Tatarskiy V.I. Wave propagation in a turbulent atmosphere. Moscow: Nauka. 1967. 548 p. (in Russian)
4. Tokovinin A. From differential image motion to seeing. Publications of the Astronomical Society of the Pacific. 2002. V. 114. № 800. P. 1156–1166. DOI 10.1086/342683.
5. Bol'basova L.A., Lukin V.P. Issues of wavefront tilt measurement. Journal of Optical Technology. 2021. V. 88. № 11. P. 625–629. DOI 10.1364/JOT.88.000625.
6. Andreeva M.S., Iroshnikov N.G., Koryabin A.B., Larichev A.V., Shmalgauzen V.I. Usage of wavefront sensor for estimation of atmos­pheric turbulence parameters. Optoelectronics, Instrumentation and Data Processing. 2012. V. 48. № 2. P. 197–204. DOI 10.3103/ S8756699012020136.
7. McGuire P.C., Langlois M.P., Lloyd-Hart M., Rhoadarmer T.A., Roger J., Angel P. Measurement of Atmospheric Turbulence with a Shack-Hartmann Wavefront Sensor at the new MMT’s Prime Focus. The International Society for Optical Engineering. 2000.
8. Brennan T.J. Turbulence characterization with a Shack-Hartmann wavefront sensor. SPIE Newsroom. DOI 10.1117/2.1201011.003316.
9. Zhang Ju., Zhao Yu., Yang L., Liu J., Wang W., Li Zh., Wang J., Chen T. Measurement of Atmospheric Coherence Length from a Shack-Hartmann Wavefront Sensor with Extended Sources. Photonics. 2024. V. 11. № 12. P. 1184. DOI 10.3390/photonics11121184.
10. Bogachev V.A., Kolokolov I.V., Lebedev V.V., Starikov F.A. Correlation matrix of light wave phase gradients as a method for measuring basic turbulence parameters. Letters to the Journal of Experimental and Theoretical Physics. 2024. V. 120. № 7-8. p. 598–604. DOI 10.31857/S0370274X24100174. (in Russian)
11. Antoshkin L.V., Botygina N.N., Emaleev O.N., Lavrinova L.N., Lukin V.P. Differential optical meter of atmospheric turbulence parameters. Optics of the atmosphere and ocean. 1998. V. 11. № 11. P. 1219–1223. (in Russian)
12. Sarazin M., Roddier F. The ESO Differential Image Motion Monitor. Astronomy & Astrophysics. 1990. V. 227. P. 294–300.
13. Tyson R.K., Frazier B.W. Principles of Adaptive Optics. 5th ed. Boca Raton. FL, USA: CRC Press. 2022.
14. Listratov A.V., Sidorov V.I. Ship optical-electronic location systems. Moscow: Moscow State Institute of Radio Engineering, Electronics and Automation (Technical University). 2007. 177 p. (in Russian)