We propose a multiconjugate adaptive optics (MCAO) system called pupil-transformation MCAO (PT-MCAO) for solar high-angular resolution imaging over a large field of view. The PT-MCAO, consisting of two deformable mirrors (DMs), uses a Shack-Hartmann w . . .

We propose a high-contrast coronagraph for direct imaging of young Jupiter-like planets orbiting nearby bright stars. The coronagraph employs a step-transmission filter in which the intensity is apodized with a finite number of steps with identical tr . . .

Future ground-based direct imaging of exoplanets depends critically on high-contrast coronagraph and wave-front manipulation. A coronagraph is designed to remove most of the unaberrated starlight. Because of the wave-front error, which is inherit from . . .

Polarimetry plays an important role in the measurement of solar magnetic fields. We developed a high-sensitivity and high-accuracy polarimeter (HHP) based on nematic liquid crystal variable retarders (LCVRs), which has a compact setup and no mechanica . . .

A method based on the Herzberger approach has been investigated for the selection of glasses for the apochromatic correction at near-infrared (NIR) wavelength. The method avoids the algebraic complexity and simplifies the glass selection processes. Do . . .

We propose a coronagraph for direct imaging of Earth‐like planets orbiting nearby bright stars. The coronagraph is based on an apodization pupil composed of two stepped‐transmission filters. We show that the coronagraph can achieve 10−10 high‐contrast . . .

Multi-conjugate adaptive optics (MCAO) can considerably extend the corrected field of view with respect to classical adaptive optics, which will benefit solar observation in many aspects. In solar MCAO, the Sun structure is utilized to provide multipl . . .

We propose a coronagraph for direct imaging of Earth‐like planets orbiting nearby bright stars. The coronagraph is based on an apodization pupil composed of two stepped‐transmission filters. We show that the coronagraph can achieve 10−10 high‐contrast . . .

A prototype of a multiway fibre bundle connector for astronomical applications is described. The connector provides for connection and disconnection in the fiber trains that feed an astronomical spectrograph. It also provides the more important functi . . .

An adaptive optics (AO) system based on stochastic parallel gradient descent (SPGD) algorithm is proposed to reduce the speckle noises in the optical system of stellar coronagraph in order to further improve the contrast. The principle of SPGD algorit . . .