A5031808173- Adaptive optics and wavefront sensing
- Optical Systems and Laser Technology
- Solar and Space Plasma Dynamics
- Optical measurement and interference techniques
- Optical Polarization and Ellipsometry
- Stellar, planetary, and galactic studies
- Solar Radiation and Photovoltaics
- Advanced optical system design
- CCD and CMOS Imaging Sensors
- Photovoltaic System Optimization Techniques
- Optical Wireless Communication Technologies
- Solar Thermal and Photovoltaic Systems
- Spectroscopy Techniques in Biomedical and Chemical Research
- Advanced Optical Sensing Technologies
- Digital Holography and Microscopy
- Optical Coherence Tomography Applications
- solar cell performance optimization
- Image Processing Techniques and Applications
- Advanced Fluorescence Microscopy Techniques
- Calibration and Measurement Techniques
- Photoreceptor and optogenetics research
- Advanced Measurement and Metrology Techniques
- Astronomical Observations and Instrumentation
- Random lasers and scattering media
- Analytical Chemistry and Sensors
National University of Defense Technology
2025
Chinese Academy of Sciences
2015-2024
Institute of Optics and Electronics, Chinese Academy of Sciences
2015-2024
University of Chinese Academy of Sciences
2010-2024
Academia Sinica
2021
ABSTRACT A high-order solar adaptive optics (AO) system including a fine tracking loop and wavefront correction has been installed at the 1 m New Vacuum Solar Telescope of Fuxian Observatory, in routine operation since 2016. The consists deformable mirror with 151 actuators, correlating Shack–Hartmann sensor 102 subapertures which Absolute Difference Square Algorithm is used to extract gradients, custom-built real-time controller based on Field-Programmable Gate Array (FPGA) multi-core...
The multi-pixel photon counter (MPPC) array-based 3D imaging is a promising technology for remote sensing. However, variations in target reflectivity can introduce range walk error (RWE) during threshold discrimination, limiting performance. This paper proposes an efficient RWE correction method MPPC array, which combines voltage modulation and macro-pixel linear regression. Using single-frame images obtained at four different voltage, the reduces depth difference between high low regions of...
DKDP modulators are widely employed in polarization measurements of solar telescopes. Accurate calibration the modulator is essential to ensure reliable measurements. In this paper, we propose a method for calibrating based on rotation and longitudinal Pockels effect. Using method, both fast-axis azimuth retardance with voltage can be simultaneously obtained. The simulation results demonstrate that achieves accuracies angle better than 0.05°. An experimental also conducted verify method's...
For better understanding and forecasting of solar activity, high resolution observations for the Sun are needed. Therefore, Chinese Large Solar Telescope (CLST) with a 1.8-m aperture is being built. The CLST classic Gregorian configuration telescope an open structure, alt-azimuth mount, retractable dome, large mechanical de-rotator. optical system all reflective design has field view larger than 3 arc-min. primary mirror honeycomb sandwich fused silica lightweight ultra lower expansion...
The first generation solar adaptive optics (AO) system, which consists of a fine tracking loop with tip-tilt mirror (TTM) and correlation tracker, high-order correction 37-element deformable (DM), correlating Shack-Hartmann (SH) wavefront sensor (WFS) based on the absolute difference algorithm real time controller (RTC), has been developed installed at 1-m New Vacuum Solar Telescope (NVST) that is part Fuxian Observatory (FSO). Compared AO system for 26-cm Fine Structure Telescope,...
In a radial shearing interferometer, portion of the test beam is magnified and used as reference for tested wavefront. However, always off center (lateral shear), which complicates wavefront reconstruction. A modal method solving this problem presented here. This uses orthogonal Zernike polynomials its matrix formalism to calculate coefficient under test. approach has easier implementation, better filtering, more adaptive practical situation. The corresponding mathematical formula deduced,...
A single-shot common-path phase-stepping radial shearing interferometer (RSI) is proposed for wavefront measurements. In the RSI, three quarter-wave plates are used as phase shifters to produce four spatially separated fringe patterns that recorded simultaneously by a single CCD camera. The RSI can measure under test in real-time, and it also insensitive environmental vibration due its structure. Experimentally applied detect distorted wavefronts generated liquid crystal spatial light...
Phase unwrapping (PU) algorithms play a crucial role in various phase measurement techniques. Traditional cannot work well strong noise environments, which makes it very difficult to obtain the accurate absolute from noisy wrapped phase. In this Letter, we introduce novel, best of our knowledge, algorithm named PD-VHS. This innovatively employs point spread function (PSF) filtering eliminate Furthermore, combines diversity (PD) wavefront reconstruction technology with virtual Hartmann-Shack...
Coating structures with dynamically adjustable infrared emissivity are crucial in spacecraft components to cope the transient thermal environments of space. For a long time, thermochromic phase change materials have been widely used applications requiring adjustment, and optimizing range has always at forefront research. However, reducing absorption solar radiation significant implications for practical application stability space environments. In this paper, we propose multilayer film...
Abstract For the public having a better understanding of solar activities, Educational Adaptive-optics Solar Telescope (EAST) was built in July 2021 and is located at Shanghai Astronomy Museum. The EAST consists 65 cm aperture telescope with 177-element adaptive optics system two-channel high resolution imaging H α TiO bands, addition to three full disk telescopes Ca K, bands equipped on tube main telescope. In this paper, configuration described. Its performance on-sky observational results...
A light-weighted primary mirror is the most important optical element for a large ground-based solar telescope. It receives radiation of more than 1000 W / m2, which about 10% converted into heat energy, bringing in seeing effect and surface shape distortion. Thus, thermal control system (TCS) necessary important. Many studies have discussed factors that influence temperature difference between ambient air, but few refer to TCS modeling optimization sake parameter estimation. model...
Shack-Hartmann wavefront sensor (SHWFS) has been widely used in adaptive optics (AO) systems to detect phase distortion characteristics. In laser communication, target detection, vision and other application fields, the performance of SHWFS is affected by bright skylight scattered light, which restricted working ability AO system severely. Therefore, this paper proposes a new polarized (p-SHWFS) based on principle polarization imaging, utilize difference state (SoP) between signal stray...
Adaptive optics systems for large-aperture solar telescopes, especially multiconjugate adaptive systems, suffer from a fundamental trade-off between wavefront sampling rate and sub-aperture resolution. We introduce an enhanced-resolution Shack-Hartmann sensing method that decouples resolution the desired rate. experimentally verified validity of this method. Results show by synthesizing multiple low-spatial samplings, is capable to sense higher-frequency aberrations beyond any involved in...
We report a compact and simultaneous polarimeter for complete Stokes polarization imaging by using an encoded birefringent crystal (EBC), micropolarizer array, camera, without any mechanical movements, electrical signal modulation, complex configuration. The EBC is made of thin piece crystal, composed identical units that have been different thickness at four neighboring pixels. Different with previous methods, this new design takes advantage retardances derives the state incident beam from...
The phase diversity wavefront sensor is one of the tools used to estimate aberration, and it often as a in adaptive optics systems. However, performance traditional limited by accuracy dynamic ranges intensity distribution at focus defocus positions CCD camera. In this paper, modified based on diffraction grating proposed improve ability measure aberration with larger amplitude higher spatial frequency. basic principle construction method are also described detail. noise propagation property...
Polarimeter by rotating polarizer is one of the well-known and classic division time polarimeter (DoTP). It generally acknowledged that this kind consuming for each measurement although it has simple, accurate compact performances. In paper we present a time-integration using continuous polarizer. The basic principle corresponding mathematical expressions are derived. Numeric analysis experiments also made in paper. Experimental results validate precision feasibility proposed imaging...
A low frequency wavefront aberration correction method for solar telescopes based on secondary mirror movement is proposed to correct dynamic during the operation of telescope. The ability this analyzed and validated by numerical simulation experiments. Theoretical analysis both indicate system processes significant given 10 times higher than frequency. After spatiotemporal division actual data from telescope, experiment result proves that can effectively reduce overall RMS aberrations with...
A low-order solar adaptive optics (AO) system, which consists of a fine tracking loop with tip/tilt mirror and correlation tracker, high-order correction 37-element deformable mirror, correlating Shack-Hartmann wavefront sensor controller, had been successfully developed installed at 1-m New Vacuum Solar Telescope Full-shine Lake (also called Fuxian Lake) Observatory. This system is an update the AO designed for 26-cm Fine Structure Yunnan Astronomical Observatory in 2009. The arrangement...
heat-stop is one of the essential thermal control devices solar telescope. The internal seeing induced by its temperature rise will degrade imaging quality significantly. For quantitative evaluation on seeing, an integrated analysis method based computational fluid dynamics and geometric optics proposed in this paper. Firstly, field heat-affected zone obtained calculation. Secondly, transformed to refractive index corresponding equations. Thirdly, wavefront aberration calculated optical...
We propose a compact phase-shifting radial shearing interferometer based on pixelated micro-retarder array (MRA). The MRA is made of thin birefringence plate, and composed identical units that have pixels four different thicknesses. demonstrate phase delay between two beams can be introduced by applying the fast axis plate in horizontal or vertical orientation. also present an approach to extract wavefront under test with random shift, which dramatically reduces machining difficulty MRA....