Recently, the results of the 10th National Undergraduate Physics Experiment Competition (Innovation) sponsored by the Joint Association of National Experimental Teaching Demonstration Centers in Higher Education, the National Research Association for Experimental Physics Teaching in Higher Education, the Physics Teaching Committee of Chinese Physical Society, and hosted by Beijing University of Aeronautics and Astronautics (BUAA), were unveiled. The CAS MICROSTAR-assisted team of undergraduates from the School of Physical Science and Technology of Xiamen University stood out among the many participating teams in the competition and won the second prize in the category of self-selected topics.
Award Details
Title of Entry: Adaptive Optical System Based on Interferometric Method to Extract Phase Information
Participating Students: Luyao Wang, Wenhao Wang (Tianwen), Kaiyu Shi, An kexin Wu
Instructor: Qinghong Lu, Jun Yin
Award-winning Works
Introduction
Adaptive optics is an important technology in modern astronomical observation. American astronomer Babcock firstly put forward the idea of “real-time measurement of wavefront error and real-time compensation of wavefront aberration caused by atmospheric turbulence and other dynamic perturbations using deformable optical elements” in 1953. At present, large telescopes at home and abroad are widely applying this technology, the Keck Telescope in Hawaii, the VLT of the European Southern Observatory and the 2.16 m telescope of the Xinglong Observatory of the National Astronomical Observatory have realized the real-time correction of atmospheric turbulence. After the realization in the field of astronomical telescope imaging, adaptive optics has been developed in many industrial and civil fields, especially in the high-precision fields of microscopes, laser systems and retinal imaging, etc. In 2008, China's first Key Laboratory of Adaptive Optics was established in the Institute of Photonics and Electronics Technology. Today, China's research level in the field of adaptive optics has stepped into the international advanced ranks.
According to different application scenarios, adaptive optics systems have many different structural forms. Among them, the adaptive optics system based on the principle of phase conjugation is the most commonly used structure. The adaptive optical system of this structure consists of three parts: wavefront sensor, wavefront controller and wavefront corrector. The light emitted from the target object is affected by atmospheric turbulence, which produces wavefront aberrations. After the aberrated beam passes through the beam splitter, part of the light wave enters the imaging system and the other part enters the wavefront sensor. Wavefront sensor real-time measurement of the phase of the incident light wave, the measurement results after the wavefront controller processing, generating the role of the wavefront corrector control signals, the wavefront corrector to generate and wavefront phase measurement results equal in size but in the opposite direction of the amount of phase correction, to compensate for atmospheric turbulence generated by the wavefront phase aberration, so that the corrected light wave into a near-plane wave.
In view of the significance of the scientific research of adaptive optics and its importance in practical applications for various industries to provide high-quality images and data, in recent years by more and more attention. At present there are individual optical instrument manufacturers can provide adaptive optics solutions suitable for laboratory, with the advantages of high spatial resolution and ultra-fast response speed, but there are generally highly integrated devices, high requirements for operators and expensive problems, which largely limits its promotion in teaching. According to the survey, the current physics and astronomy teaching in domestic colleges and universities basically does not involve adaptive optics-related experiments. To this end, a team of undergraduates from Xiamen University, under the guidance of teachers, built a set of adaptive optics system based on interferometric method to extract phase information, replacing expensive wavefront sensors with optical interferometric system, recovering the wavefront phase through certain algorithms; replacing deformable mirrors or microlens arrays with spatial light modulators (SLMs) to modulate the phase and amplitude of light waves, realizing the calibration of the test images in the laboratory, and realizing the correction of the test images without affecting the The cost of the device has been greatly reduced without affecting the teaching effect, which fills the gap of adaptive optics in experimental teaching.
Experimental setup
Company Support and Vision
As a real-time programmable digital optical core device, the spatial light modulator has many application possibilities in the National University Physics Experiment Competition; it can be used as a real-time programmable diffractive element for single-slit, double-slit, grating, triangle, pentagram, hexagon, etc.; it can be used as a programmable filter for low-pass, high-pass, and slit filters; it can be used as an alternative to a mask plate; it can be used to perform projection; it can generate vortex light It can produce vortex light, Bessel light, Airy beam; it can replace the rotating hair glass to produce pseudo-thermal light field; it can simulate atmospheric turbulence; it can also be a holographic element; research and experiments based on the spatial light modulator will be of great benefit to the exercise of the students' self-development capabilities and pioneering thinking.
As a company focusing on the field of optoelectronic science and technology, CSC MicroStar has always been committed to promoting scientific and technological innovation and talent cultivation. This time, CSC MicroStar provided the participating team with a free experimental equipment of our company's spatial light modulator (FSLM-2K39-P), which provided a strong guarantee for them to achieve good results in the competition. The technical parameters of this spatial light modulator (FSLM-2K39-P) are as follows:
Model |
FSLM-2K39-P |
Modulation |
Phase-only |
LCOS type |
Reflection |
Grayscale level |
8 bits, 256 steps |
LCOS mode |
PAN |
Driving method |
Digital signal |
Resolution |
1920×1080 |
Image Size |
4.5μm |
Effective area |
0.39" |
phase range |
|
Fill factor |
91.3% |
Optical Utilization |
75%@532nm |
Response time |
≤16.7ms |
Matching angle |
0° |
Face Correction |
not support |
spectral range |
420nm-650nm |
Refresh frequency |
60Hz |
Input Power |
5V 2A |
Phase Stability (RMS) |
≤0.01π |
linearity |
≥99% |
Flatness (PV) |
Before calibration: 1.0λ After calibration: 0.3λ |
Flatness (RMS) |
Before calibration: 1/5λ After calibration: 1/20λ |
Damage threshold |
20W/cm² |
Data interfaces |
Mini DP |
Product Features:
King of the domestic and foreign reflective pure phase product market price/performance ratio; Synchronized trigger function, excellent reflective wavefront characteristics; High utilization, high fill factor, low phase jitter, high diffraction efficiency; Measured phase modulation capability, good phase linearity; Can be customized according to the user's needs.
Application areas:
Wavefront correction (can be used for adaptive optics); beam shaping (generation of vortex light, flat-top light shaping, ring beam); beam control (beam deflection, plane beam splitting, curved surface beam splitting, depth-of-focus extension); beam collimation, aberration correction, programmable phase mask; computational holography; and so on.
CAS MICROSTAR has always been actively concerned about and supported all kinds of scientific and technological competitions. We provide free experimental equipment to the participating teams in this competition, aiming at improving the ability of university students in physics experiments, fostering the spirit of innovation and teamwork, and promoting the reform of physics experimental teaching and development of experimental technology, and we hope that by taking advantage of this opportunity, we can stimulate more young people's interest in and enthusiasm for optics experiments, and cultivate more scientific and technological talents for the country. At the same time, we also hope that this opportunity will inspire more young people to be interested in and enthusiastic about optical experiments, so as to cultivate more scientific and technological talents for the country.