Diffraction-limited visible imaging with piezoelectric deformable secondary mirror

The adaptive telescope based on a deformable secondary mirror can effectively simplify the system structure, enhance the telescope’s utilization of light energy, reduce background radiation, and improve the telescope’s observation ability for dim and infrared targets. This paper presents our latest research on adaptive telescopes utilizing piezoelectric deformable secondary mirrors (PDSM). We have developed a 241-unit PDSM with small actuator spacing and installed it on the 1.8-meter adaptive telescope at the Lijiang Observatory in Yunnan, China. This system has successfully captured high-resolution visible near-diffraction limit images of astronomical targets. The imaging Strehl ratio of the system in the visible light band (approximately 640nm) reaches about 0.5, and the tracking accuracy is approximately 0.02 arcseconds. These results suggest that adaptive telescopes utilizing piezoelectric-driven deformable secondary mirrors outperform traditional ’telescope + adaptive optics’ system architecture, enabling significant improvements in high-resolution visible imaging.