In this article, a method for measuring the performance of adaptive optics （AO） systems is designed and validated by experiments. The Strehl ratio （SR） which is based on the target images is used to evaluate the p...In this article, a method for measuring the performance of adaptive optics （AO） systems is designed and validated by experiments. The Strehl ratio （SR） which is based on the target images is used to evaluate the performance quantitatively because it relates to the effect of AO correction directly. In the calculation of the SR, to avoid energy scaling in the diffraction-limited point spread function, an algorithm based on the integral of the optical transfer function （OTF） is proposed. Then, a 97-element AO system is established to validate this method, and a white-light fiber source is used as a point-like target. To simulate the practical conditions which influence the performance of the AO system, targets of different brightness are simulated in terms of different signal-to-noise ratios （SNRs） of the Shack-Hartmann （SH）, and atmospheric turbulence is simulated in terms of the Fried＇s coherence length and the Greenwood＇s frequency. Finally, two experiments are conducted in which the SR of different simulated conditions are measured. The results of the experiments show that for a moderate SNR of SH the experimenting AO system is capable of closed-loop wavefront correction when the Fried＇s coherence length is larger than 5cm and the Greenwood＇s frequency is lower than 60 Hz. The results also show that the performance of AO is susceptible to the SNR of SH. The experiments validates the effectiveness of this method.展开更多
Several pupil filtering techniques have been developed in the last few years to obtain transverse superresolution （a narrower point spread function core）. Such a core decrease entails two relevant limitations： a de...Several pupil filtering techniques have been developed in the last few years to obtain transverse superresolution （a narrower point spread function core）. Such a core decrease entails two relevant limitations： a decrease of the peak intensity and an increase of the sidelobe intensity. Here, we calculate the Strehl ratio as a function of the core size for the most used binary phase filters. Furthermore, we show that this relation approaches the fundamental limit of the attainable Strehl ratio at the focal plane for any filter. Finally, we show the calculation of the peak-to-sidelobe ratio in order to check the system viability in every application.展开更多
基金supported by the National High Technology Research and Development Program of China (2014AAXXX1003X)
文摘In this article, a method for measuring the performance of adaptive optics （AO） systems is designed and validated by experiments. The Strehl ratio （SR） which is based on the target images is used to evaluate the performance quantitatively because it relates to the effect of AO correction directly. In the calculation of the SR, to avoid energy scaling in the diffraction-limited point spread function, an algorithm based on the integral of the optical transfer function （OTF） is proposed. Then, a 97-element AO system is established to validate this method, and a white-light fiber source is used as a point-like target. To simulate the practical conditions which influence the performance of the AO system, targets of different brightness are simulated in terms of different signal-to-noise ratios （SNRs） of the Shack-Hartmann （SH）, and atmospheric turbulence is simulated in terms of the Fried＇s coherence length and the Greenwood＇s frequency. Finally, two experiments are conducted in which the SR of different simulated conditions are measured. The results of the experiments show that for a moderate SNR of SH the experimenting AO system is capable of closed-loop wavefront correction when the Fried＇s coherence length is larger than 5cm and the Greenwood＇s frequency is lower than 60 Hz. The results also show that the performance of AO is susceptible to the SNR of SH. The experiments validates the effectiveness of this method.
基金supported by the by the Ministerio de Economía y Competitividad under project FIS2012-31079
文摘Several pupil filtering techniques have been developed in the last few years to obtain transverse superresolution （a narrower point spread function core）. Such a core decrease entails two relevant limitations： a decrease of the peak intensity and an increase of the sidelobe intensity. Here, we calculate the Strehl ratio as a function of the core size for the most used binary phase filters. Furthermore, we show that this relation approaches the fundamental limit of the attainable Strehl ratio at the focal plane for any filter. Finally, we show the calculation of the peak-to-sidelobe ratio in order to check the system viability in every application.
