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Geometric Optics|84 Article(s)
Characteristics of Solar Radiation Reception by Solar Wing Based on Congruent Concentrating Surface
Haibo Zhao, Xin Dai, and Fei Chen
ObjectiveThe growing emphasis on renewable energy sources in sustainable societies is evident, indicating a shift towards cleaner energy solutions. Solar photovoltaic modules harness solar radiation to generate electricity and meet the power requirements for the normal operation of instruments and devices. Typically, there are two primary approaches to increasing electricity generation, including using high-efficiency solar panels and expanding the deployment areas of solar arrays. However, the former approach has limitations in improving efficiency, while the latter significantly increases the satellite launch cost. Non-imaging solar compound parabolic concentrators have caught considerable attention due to their efficient and stable operation, easy construction, and compatibility with satellite systems for reducing energy costs and improving the effective payload capacity of satellites. The utilization of solar concentrators in satellite systems enhances sunlight capture by solar wings, thus increasing energy output, reducing weight and volume, improving the stability and durability of solar panels, and expanding the application range of concentrators. Taking these advantages into account, we design a truncated compound planar concentrator for the operational characteristics of solar wings. Coupled with real-time sun-earth distance, earth-satellite space relationships, and solar radiation theory, a model for receiving solar radiation by solar wings is developed. The findings provide valuable insights for the structural design and optimization of solar wings.MethodsFirst, via carefully analyzing the shortcomings of traditional S-CPC systems, a TMS-CPC surface structure is designed based on the edge-ray tracing principle, and its three-dimensional geometry is modeled by software. Meanwhile, a scaled-down model is built using 3D printing technology to verify the focusing performance of the constructed TMS-CPC. In the ground laboratory, parallel lasers are employed to simulate sunlight and enable visual ray tracing of the coupled TMS-CPC system. This allows for observing and recording the concentration process and characteristics of TMS-CPC on "solar rays". Simultaneously, optical simulation software is adopted for ray tracing simulations, and the obtained experimental values are compared and analyzed against the simulated values to validate the model reliability. Secondly, by considering the spatial relationships among the sun, the earth, and the satellite, a real-time distance model is built. The solar radiation amount received by the solar wing can be calculated via spatial radiation theory. Simulations and analyses are conducted using the Satellite Tool Kit (STK) to study the characteristics of solar wing reception of solar radiation based on a congruent concentrating surface.Results and DiscussionsDuring the laser validation experiment of the solar wing TMS-CPC, factors such as the laser divergence angle, high reflectivity of the flexible reflective membrane, and manufacturing errors associated with 3D printing all affect the experimental results. However, in this scenario, the simulated values of the concentrating performance of the solar wing TMS-CPC tend to align with the experimental values, with a maximum average absolute error of 1.49 mm and a minimum of 0.75 mm (Fig. 3). When the incident angle of the light exceeds 6°, optical efficiency decreases within the TMS-CPC system (Fig. 4). A comparison between the theoretical and simulation values of solar radiation on the solar wing, along with the satellite exposure characteristics, reveals an average absolute error of only 0.04 W/m2 in the radiation model calculation values and 18.2 s in satellite exposure characteristics (Fig. 7 and Table 1). During variation analysis in energy flux density on the solar surface with different incident angles of sunlight, it is observed that in the constructed solar wing TMS-CPC system, when sunlight is incident vertically (at an angle of 0°), the energy flux density on the surface of the solar panels is symmetrically distributed on both sides of the central axis. However, when sunlight is incident at angles within the acceptance half-angle (0°, 1°, and 2°), the peak energy flux density increases with the rising incident angle, while the average energy flux density remains constant (Fig. 8). The closer distance of the incident angle to the acceptance half-angle leads to more uniform distribution of energy flux density on the solar panel surface (Fig. 9). Theoretical peak power generation with the solar wing TMS-CPC is approximately 87% higher than that of traditional solar wings. However, there is a reverse trend in power generation with variations in sun-satellite distance (Fig. 10).ConclusionsOur study is based on the edge-ray tracing principle to construct a truncated structure compound planar concentrator TMS-CPC, and incorporates real-time sun-earth distance calculations, earth-satellite spatial relationships, and solar radiation theory to build a model for solar radiation reception by solar wings. Laser experiment results show that the experimental data are in good agreement with the simulation results, thereby confirming the reliability of the built model. The solar wing TMS-CPC expands the acceptable angle range beyond that of the conventional S-CPC, providing sufficient error margin in satellite tracking systems. Significantly, within the acceptance half-angle range, the average uniformity index on the solar panel surface reaches 0.615, greatly enhancing its capability to capture solar radiation. During one orbital cycle, the satellite predominantly stays in the sunlit region, ensuring favorable conditions for photovoltaic components of the solar panels and guaranteeing the satellite's long-term stable operation. This reduces energy costs and enhances overall economic benefits for satellites. Numerical simulations of power generation from a single solar wing coupled with TMS-CPC, along with a comparative analysis against traditional solar wings, illustrate that the built model effectively enhances theoretical power generation. ObjectiveThe growing emphasis on renewable energy sources in sustainable societies is evident, indicating a shift towards cleaner energy solutions. Solar photovoltaic modules harness solar radiation to generate electricity and meet the power requirements for the normal operation of instruments and devices. Typically, there are two primary approaches to increasing electricity generation, including using high-efficiency solar panels and expanding the deployment areas of solar arrays. However, the former approach has limitations in improving efficiency, while the latter significantly increases the satellite launch cost. Non-imaging solar compound parabolic concentrators have caught considerable attention due to their efficient and stable operation, easy construction, and compatibility with satellite systems for reducing energy costs and improving the effective payload capacity of satellites. The utilization of solar concentrators in satellite systems enhances sunlight capture by solar wings, thus increasing energy output, reducing weight and volume, improving the stability and durability of solar panels, and expanding the application range of concentrators. Taking these advantages into account, we design a truncated compound planar concentrator for the operational characteristics of solar wings. Coupled with real-time sun-earth distance, earth-satellite space relationships, and solar radiation theory, a model for receiving solar radiation by solar wings is developed. The findings provide valuable insights for the structural design and optimization of solar wings.MethodsFirst, via carefully analyzing the shortcomings of traditional S-CPC systems, a TMS-CPC surface structure is designed based on the edge-ray tracing principle, and its three-dimensional geometry is modeled by software. Meanwhile, a scaled-down model is built using 3D printing technology to verify the focusing performance of the constructed TMS-CPC. In the ground laboratory, parallel lasers are employed to simulate sunlight and enable visual ray tracing of the coupled TMS-CPC system. This allows for observing and recording the concentration process and characteristics of TMS-CPC on "solar rays". Simultaneously, optical simulation software is adopted for ray tracing simulations, and the obtained experimental values are compared and analyzed against the simulated values to validate the model reliability. Secondly, by considering the spatial relationships among the sun, the earth, and the satellite, a real-time distance model is built. The solar radiation amount received by the solar wing can be calculated via spatial radiation theory. Simulations and analyses are conducted using the Satellite Tool Kit (STK) to study the characteristics of solar wing reception of solar radiation based on a congruent concentrating surface.Results and DiscussionsDuring the laser validation experiment of the solar wing TMS-CPC, factors such as the laser divergence angle, high reflectivity of the flexible reflective membrane, and manufacturing errors associated with 3D printing all affect the experimental results. However, in this scenario, the simulated values of the concentrating performance of the solar wing TMS-CPC tend to align with the experimental values, with a maximum average absolute error of 1.49 mm and a minimum of 0.75 mm (Fig. 3). When the incident angle of the light exceeds 6°, optical efficiency decreases within the TMS-CPC system (Fig. 4). A comparison between the theoretical and simulation values of solar radiation on the solar wing, along with the satellite exposure characteristics, reveals an average absolute error of only 0.04 W/m2 in the radiation model calculation values and 18.2 s in satellite exposure characteristics (Fig. 7 and Table 1). During variation analysis in energy flux density on the solar surface with different incident angles of sunlight, it is observed that in the constructed solar wing TMS-CPC system, when sunlight is incident vertically (at an angle of 0°), the energy flux density on the surface of the solar panels is symmetrically distributed on both sides of the central axis. However, when sunlight is incident at angles within the acceptance half-angle (0°, 1°, and 2°), the peak energy flux density increases with the rising incident angle, while the average energy flux density remains constant (Fig. 8). The closer distance of the incident angle to the acceptance half-angle leads to more uniform distribution of energy flux density on the solar panel surface (Fig. 9). Theoretical peak power generation with the solar wing TMS-CPC is approximately 87% higher than that of traditional solar wings. However, there is a reverse trend in power generation with variations in sun-satellite distance (Fig. 10).ConclusionsOur study is based on the edge-ray tracing principle to construct a truncated structure compound planar concentrator TMS-CPC, and incorporates real-time sun-earth distance calculations, earth-satellite spatial relationships, and solar radiation theory to build a model for solar radiation reception by solar wings. Laser experiment results show that the experimental data are in good agreement with the simulation results, thereby confirming the reliability of the built model. The solar wing TMS-CPC expands the acceptable angle range beyond that of the conventional S-CPC, providing sufficient error margin in satellite tracking systems. Significantly, within the acceptance half-angle range, the average uniformity index on the solar panel surface reaches 0.615, greatly enhancing its capability to capture solar radiation. During one orbital cycle, the satellite predominantly stays in the sunlit region, ensuring favorable conditions for photovoltaic components of the solar panels and guaranteeing the satellite's long-term stable operation. This reduces energy costs and enhances overall economic benefits for satellites. Numerical simulations of power generation from a single solar wing coupled with TMS-CPC, along with a comparative analysis against traditional solar wings, illustrate that the built model effectively enhances theoretical power generation.
Acta Optica Sinica
- Publication Date: Feb. 10, 2024
- Vol. 44, Issue 3, 0308001 (2024)
High-Temperature Material Spectral Emissivity Measurement Technology Based on 800 mm Semi-Ellipsoidal Reflector
Yongxing Yang, Xinrui Wang, Beibei Chen, Hengrui Guan, Jinpeng Li, Jingyuan Zhang, Xinhua Lai, and Jinbiao Zhao
To solve the problem of material emissivity measurement at medium-high temperature, a high-temperature material spectral emissivity measurement technology based on semi-ellipsoidal reflector is proposed. In this technology, a 800 mm semi-ellipsoidal mirror is used to focus the signal light in a large range, three kinds of off-axis parabolic mirrors are used to switch different test fields of view, and the sample is heated by a high-power laser. The measurement error of the designed system is studied in simulation. The results show that the maximum measurement deviation of reflectivity is 0.035, and that of transmittance is 0.031. An emissivity measurement system based on a 800 mm semi-ellipsoidal mirror is constructed. Then, the reflectivity, transmittance, and emissivity of an alloy material and a translucent material are measured, which shows that the designed system can realize the measurement from normal temperature to medium-high temperature (300--1200 K), multi-field of view (30°, 60°, 90°), and wide spectrum (2--14 μm). To solve the problem of material emissivity measurement at medium-high temperature, a high-temperature material spectral emissivity measurement technology based on semi-ellipsoidal reflector is proposed. In this technology, a 800 mm semi-ellipsoidal mirror is used to focus the signal light in a large range, three kinds of off-axis parabolic mirrors are used to switch different test fields of view, and the sample is heated by a high-power laser. The measurement error of the designed system is studied in simulation. The results show that the maximum measurement deviation of reflectivity is 0.035, and that of transmittance is 0.031. An emissivity measurement system based on a 800 mm semi-ellipsoidal mirror is constructed. Then, the reflectivity, transmittance, and emissivity of an alloy material and a translucent material are measured, which shows that the designed system can realize the measurement from normal temperature to medium-high temperature (300--1200 K), multi-field of view (30°, 60°, 90°), and wide spectrum (2--14 μm).
Acta Optica Sinica
- Publication Date: May. 05, 2022
- Vol. 42, Issue 9, 0908001 (2022)
Research and Design of Variable Curvature Optical Integrator for Solar Simulator
Haowen Peng, Shi Su, Guoyu Zhang, Shi Liu, Gaofei Sun, Jian Zhang, Fanlin Meng, and Yongzhu Chen
In order to solve the problem of low radiation energy at the edge of the output spot of the equal curvature optical integrator, which leads to the poor uniformity of the radiation surface, the differential and integration method of radiation energy based on the diffraction theory is proposed, and a variable curvature optical integrator is designed. The aperture and number of the integrator channel are determined according to the Fresnel number, and the radiation distribution curve is divided equidistant. According to the difference of the focal length of each eye lens in the integrator, the radiation distribution curve is superimposed step by step. Based on the diffraction theory, the mathematical model of variable curvature optical integrator in two-dimensional plane is established, and the mathematical function of light intensity distribution on the working face is deduced. The aspheric optimization design of each circle eye lens in the field lens group is carried out by using Zemax software to improve the imaging quality and eliminate the sidelobe effect. The variable curvature optical integrator and the constant curvature optical integrator are simulated by LightTools software, and their performance differences are compared and analyzed. The results show that the variable curvature optical integrator can significantly improve the edge radiation energy of the output spot of the solar simulator, up to 56% higher than that of the equal curvature optical integrator, the irradiation non-uniformity in the Φ100 mm radiation plane is better than ±0.5%, and the radiation inhomogeneity in the Φ200 mm radiation plane is better than ±1%. In order to solve the problem of low radiation energy at the edge of the output spot of the equal curvature optical integrator, which leads to the poor uniformity of the radiation surface, the differential and integration method of radiation energy based on the diffraction theory is proposed, and a variable curvature optical integrator is designed. The aperture and number of the integrator channel are determined according to the Fresnel number, and the radiation distribution curve is divided equidistant. According to the difference of the focal length of each eye lens in the integrator, the radiation distribution curve is superimposed step by step. Based on the diffraction theory, the mathematical model of variable curvature optical integrator in two-dimensional plane is established, and the mathematical function of light intensity distribution on the working face is deduced. The aspheric optimization design of each circle eye lens in the field lens group is carried out by using Zemax software to improve the imaging quality and eliminate the sidelobe effect. The variable curvature optical integrator and the constant curvature optical integrator are simulated by LightTools software, and their performance differences are compared and analyzed. The results show that the variable curvature optical integrator can significantly improve the edge radiation energy of the output spot of the solar simulator, up to 56% higher than that of the equal curvature optical integrator, the irradiation non-uniformity in the Φ100 mm radiation plane is better than ±0.5%, and the radiation inhomogeneity in the Φ200 mm radiation plane is better than ±1%.
Acta Optica Sinica
- Publication Date: Mar. 24, 2022
- Vol. 42, Issue 7, 0708001 (2022)
Numerical Aperture Optimization of Microlens for Curved Integral Imaging
Wenwen Wang, Xiongtu Zhou, Yongai Zhang, Chaoxing Wu, Zhixian Lin, and Tailiang Guo
Present three-dimensional (3D) display systems based on integral imaging have small field of view and low resolution of reconstructed images. To overcome these limitations, a flexible microlens array structure with different numerical apertures suitable for curved integral imaging 3D display is designed and successfully built on curved screen. The optical simulation software of Trace Pro is used to establish a curved integral imaging 3D display system model. Further, the influence of the numerical aperture of the microlens on the reconstruction performance of the curved integral imaging 3D display system is investigated. The results show that for microlens with a constant size and thickness, the larger the numerical aperture, the better the quality of the reconstructed image and larger the field of view. However, if the numerical aperture of the flexible microlens array is 0.376, the reconstructed image will have a higher resolution. Moreover, when the field of view reaches 60°, the reconstructed image is still clear. For simulation verification, flexible microlens arrays with different numerical apertures are prepared and a prototype of the curved integral imaging system is constructed. The experimental results are consistent with the simulation results. Present three-dimensional (3D) display systems based on integral imaging have small field of view and low resolution of reconstructed images. To overcome these limitations, a flexible microlens array structure with different numerical apertures suitable for curved integral imaging 3D display is designed and successfully built on curved screen. The optical simulation software of Trace Pro is used to establish a curved integral imaging 3D display system model. Further, the influence of the numerical aperture of the microlens on the reconstruction performance of the curved integral imaging 3D display system is investigated. The results show that for microlens with a constant size and thickness, the larger the numerical aperture, the better the quality of the reconstructed image and larger the field of view. However, if the numerical aperture of the flexible microlens array is 0.376, the reconstructed image will have a higher resolution. Moreover, when the field of view reaches 60°, the reconstructed image is still clear. For simulation verification, flexible microlens arrays with different numerical apertures are prepared and a prototype of the curved integral imaging system is constructed. The experimental results are consistent with the simulation results.
Acta Optica Sinica
- Publication Date: Mar. 06, 2022
- Vol. 42, Issue 5, 0508002 (2022)
Influence of Absorber Shape on Photothermal Performance of Solar Compound Multi-Surface Concentrator
Zehui Chang, Xuedong Liu, Jing Liu, Hongfei Zheng, and Xinglong Ma
In order to reduce the construction cost of a compound multi-surface concentrator and improve its utilization efficiency of solar energy, the single-layer glass tube embedded absorber is selected as the photothermal conversion component of a compound multi-surface concentrator. The influence mechanism of the absorbers with different shapes in the single-layer glass tube on the photothermal performance of a compound multi-surface concentrator is mainly studied. First, the optical model of the concentrator is established in the optical simulation software TracePro, and the influence mechanism of absorber shapes on the optical performance of the concentrator is simulated and analyzed based on the Monte Carlo algorithm. Then, the influence of absorber shapes on the outlet temperature, instantaneous heating collection and photothermal conversion efficiency of the concentrator are analyzed. The results show that under the same incident angle, the number of light received by the “*”-shaped absorber is more than that received by the rectangular mesh receiver. When the incident angle is in the range of 0°--20°, the average light receiving rate and the average concentrating efficiency of the concentrator embedded with the“*”-shaped absorber are 7.37% and 6.66% higher than that of concentrator embedded with the rectangular mesh receiver, respectively. Under sunny weather conditions, the average outlet temperature, average discrepancy between air temperature of inlet and outlet, average instantaneous heating collection and average photothermal conversion efficiency of the concentrator embedded with “*”-shaped receiver are 48.5 ℃, 23.2 ℃, 467.5 W and 54.85%, respectively, which are 43.07%, 31.82%, 29.83% and 24.52% higher than that of the rectangular mesh receiver, respectively. In order to reduce the construction cost of a compound multi-surface concentrator and improve its utilization efficiency of solar energy, the single-layer glass tube embedded absorber is selected as the photothermal conversion component of a compound multi-surface concentrator. The influence mechanism of the absorbers with different shapes in the single-layer glass tube on the photothermal performance of a compound multi-surface concentrator is mainly studied. First, the optical model of the concentrator is established in the optical simulation software TracePro, and the influence mechanism of absorber shapes on the optical performance of the concentrator is simulated and analyzed based on the Monte Carlo algorithm. Then, the influence of absorber shapes on the outlet temperature, instantaneous heating collection and photothermal conversion efficiency of the concentrator are analyzed. The results show that under the same incident angle, the number of light received by the “*”-shaped absorber is more than that received by the rectangular mesh receiver. When the incident angle is in the range of 0°--20°, the average light receiving rate and the average concentrating efficiency of the concentrator embedded with the“*”-shaped absorber are 7.37% and 6.66% higher than that of concentrator embedded with the rectangular mesh receiver, respectively. Under sunny weather conditions, the average outlet temperature, average discrepancy between air temperature of inlet and outlet, average instantaneous heating collection and average photothermal conversion efficiency of the concentrator embedded with “*”-shaped receiver are 48.5 ℃, 23.2 ℃, 467.5 W and 54.85%, respectively, which are 43.07%, 31.82%, 29.83% and 24.52% higher than that of the rectangular mesh receiver, respectively.
Acta Optica Sinica
- Publication Date: Mar. 06, 2022
- Vol. 42, Issue 5, 0508001 (2022)
Non-Gap Loss of Compound Parabolic Concentrator with Solar Vacuum Tube as Absorber
Fei Chen, and Qinghua Gui
Based on the principle of non-imaging optical edge light and the law of geometric optical reflection, the mathematical model of the surface structure of compound parabolic concentrator (CPC) without gap loss is constructed for circular absorber, and the numerical solution of the equal-length reflector is obtained by program calculation. The CPC model without gap loss is verified by a visible laser experimental device, and the results show that the light path calculated by numerical method is consistent with that of laser experiment. Moreover, the CPC without gap loss of a single pair of equal-length reflectors has the largest length of a single equal-length reflector, which is exactly the radius of the absorber. When the number of equal-length reflectors increases from single pair to 6 pairs, the length of a single equal-length reflector decreases from 23.50 mm to 7.65 mm. In the process of practical application, the number of pairs of equal-length reflectors should not be too much. Based on the principle of non-imaging optical edge light and the law of geometric optical reflection, the mathematical model of the surface structure of compound parabolic concentrator (CPC) without gap loss is constructed for circular absorber, and the numerical solution of the equal-length reflector is obtained by program calculation. The CPC model without gap loss is verified by a visible laser experimental device, and the results show that the light path calculated by numerical method is consistent with that of laser experiment. Moreover, the CPC without gap loss of a single pair of equal-length reflectors has the largest length of a single equal-length reflector, which is exactly the radius of the absorber. When the number of equal-length reflectors increases from single pair to 6 pairs, the length of a single equal-length reflector decreases from 23.50 mm to 7.65 mm. In the process of practical application, the number of pairs of equal-length reflectors should not be too much.
Acta Optica Sinica
- Publication Date: Dec. 27, 2021
- Vol. 42, Issue 2, 0208001 (2022)
Effect of Secondary Concentrator with Straight Funnel on Performance of Single-Spectrum Xenon Lamp-Thermophotovoltaic System
Xiuli Liu, Xue Chen, Chuang Sun, and Xinlin Xia
A test system is designed for evaluating the characteristics of single-spectrum radiant energy-electricity energy conversion of thermophotovoltaic cells. A band-pass filter and a secondary concentrator with a straight funnel are used to achieve single-spectrum and directional radiation transmission between the xenon lamp and the thermophotovoltaic cells with adjustable energy flux density. Based on Monte-Carlo ray tracing method, the spectral radiation transmission model of the xenon lamp-thermophotovoltaic test system is constructed. The distribution characteristics of radiant energy flux on the cell surface are analyzed, and the effects of opening size and height of the secondary concentrator are discussed. Meanwhile, the current-voltage curve, output power, and thermoelectric conversion efficiency of GaSb cell under single-spectrum and high energy flux radiation are theoretically calculated. The results show that the introduction of a secondary concentrator can effectively improve the thermoelectric conversion performance of the thermophotovoltaic cells. The radiant energy on the cell surface increases by 105.3%, with the uniformity reaching 95%, and the output power of the cell increases by 109.1%. A test system is designed for evaluating the characteristics of single-spectrum radiant energy-electricity energy conversion of thermophotovoltaic cells. A band-pass filter and a secondary concentrator with a straight funnel are used to achieve single-spectrum and directional radiation transmission between the xenon lamp and the thermophotovoltaic cells with adjustable energy flux density. Based on Monte-Carlo ray tracing method, the spectral radiation transmission model of the xenon lamp-thermophotovoltaic test system is constructed. The distribution characteristics of radiant energy flux on the cell surface are analyzed, and the effects of opening size and height of the secondary concentrator are discussed. Meanwhile, the current-voltage curve, output power, and thermoelectric conversion efficiency of GaSb cell under single-spectrum and high energy flux radiation are theoretically calculated. The results show that the introduction of a secondary concentrator can effectively improve the thermoelectric conversion performance of the thermophotovoltaic cells. The radiant energy on the cell surface increases by 105.3%, with the uniformity reaching 95%, and the output power of the cell increases by 109.1%.
Acta Optica Sinica
- Publication Date: Aug. 25, 2022
- Vol. 42, Issue 15, 1508001 (2022)
Method for Improving Geometric Calibration Accuracy of Directional Polarimetric Camera Based on Relative Response Correction
Guangfeng Xiang, Binghuan Meng, Shuang Li, Lin Han, Tingrui Sheng, Liang Sun, Donggen Luo, and Jin Hong
High-precision centroid positioning is the key to the geometric calibration method based on a single collimator and a separated two-dimensional turntable. However, the relative response difference of the instrument will affect the centroid positioning accuracy. Therefore, a centroid positioning accuracy improvement method based on the relative response correction is proposed, which can effectively improve the centroid positioning accuracy, thereby improving the geometric calibration accuracy. The laboratory geometric calibration experiment based on the directional polarimetric camera proves the improvement effect of the proposed method. The improvement effect is more significant in the large field of view area, and the maximum geometric calibration accuracy is about 0.1 pixel. Finally, based on the proposed centroid positioning accuracy improvement method, the geometric model parameters of high-precision directional polarimetric camera are obtained in the laboratory, and the model fitting residual is better than 0.1 pixel. High-precision centroid positioning is the key to the geometric calibration method based on a single collimator and a separated two-dimensional turntable. However, the relative response difference of the instrument will affect the centroid positioning accuracy. Therefore, a centroid positioning accuracy improvement method based on the relative response correction is proposed, which can effectively improve the centroid positioning accuracy, thereby improving the geometric calibration accuracy. The laboratory geometric calibration experiment based on the directional polarimetric camera proves the improvement effect of the proposed method. The improvement effect is more significant in the large field of view area, and the maximum geometric calibration accuracy is about 0.1 pixel. Finally, based on the proposed centroid positioning accuracy improvement method, the geometric model parameters of high-precision directional polarimetric camera are obtained in the laboratory, and the model fitting residual is better than 0.1 pixel.
Acta Optica Sinica
- Publication Date: Jun. 05, 2022
- Vol. 42, Issue 12, 1208001 (2022)
Design of Freeform Off-Axis Reflective Afocal Systems by Orthogonal Seed Curve Extension Algorithm
Xingtao Chen, Zhouping Su, Yangliu Zhang, and Lifa Hu
Off-axis reflective afocal optical systems have important applications in space telescopes. Freeform surfaces can correct the asymmetric aberrations in off-axis reflective afocal systems. It is very important to design the initial layouts of freeform off-axis reflective afocal systems. In this paper, an orthogonal seed curve extension (OSCE) algorithm was proposed to design the initial layouts of freeform off-axis reflective afocal systems directly. Off-axis afocal three-mirror and four-mirror systems with magnifications of 10 and 20, respectively, were designed to verify the feasibility of the method. The results show that the root-mean-square (RMS) wavefront error of the initial layout of the off-axis three-mirror system is 0.36 λ, and that of the off-axis four-mirror system is 0.18 λ. The RMS wavefront errors of the two initial layouts after optimization are both less than 0.02 λ. Off-axis reflective afocal optical systems have important applications in space telescopes. Freeform surfaces can correct the asymmetric aberrations in off-axis reflective afocal systems. It is very important to design the initial layouts of freeform off-axis reflective afocal systems. In this paper, an orthogonal seed curve extension (OSCE) algorithm was proposed to design the initial layouts of freeform off-axis reflective afocal systems directly. Off-axis afocal three-mirror and four-mirror systems with magnifications of 10 and 20, respectively, were designed to verify the feasibility of the method. The results show that the root-mean-square (RMS) wavefront error of the initial layout of the off-axis three-mirror system is 0.36 λ, and that of the off-axis four-mirror system is 0.18 λ. The RMS wavefront errors of the two initial layouts after optimization are both less than 0.02 λ.
Acta Optica Sinica
- Publication Date: Dec. 21, 2021
- Vol. 42, Issue 1, 0108001 (2022)
Analysis of Optomechanical Characteristics of Semi-Ellipsoidal Mirrors for Measuring High-Temperature Optical Parameters of Materials
Hengrui Guan, Fenghua Zheng, Wenxiang Li, Chao Kang, Yongxing Yang, and Jinpeng Li
In order to improve the light energy utilization of equipment for measuring high-temperature optical parameters of materials and obtain better irradiance on the surface of the sample to be tested, a semi-ellipsoidal reflector is applied to the equipment. First, the equipment for measuring high-temperature optical parameters of materials and the role of the semi-ellipsoidal mirror in the equipment are introduced. Then, the optical characteristics and surface shape changes of semi-ellipsoidal mirrors are analyzed by using ray tracing and finite element analysis methods, and the influence of surface shape change of the semi-ellipsoidal mirror at 30 ℃ on optical characteristics is analyzed. Finally, the shape of the inner surface of the semi-ellipsoid mirror is measured by the three-coordinate measurement instrument, and the simulation results are verified. Experimental results show that: at 30 ℃, the root mean square (RMS) of the deformation of the semi-ellipsoidal mirror after removing ellipsoid deformation is 2.15 μm, the irradiation uniformity obtained by using a Φ15 mm blackbody radiation source is 61%, the energy utilization is 7.6%, and the RMS is 5.75 μm measured by the three-coordinate measuring instrument. This study provides a new way to measure high-temperature optical parameters of materials. In order to improve the light energy utilization of equipment for measuring high-temperature optical parameters of materials and obtain better irradiance on the surface of the sample to be tested, a semi-ellipsoidal reflector is applied to the equipment. First, the equipment for measuring high-temperature optical parameters of materials and the role of the semi-ellipsoidal mirror in the equipment are introduced. Then, the optical characteristics and surface shape changes of semi-ellipsoidal mirrors are analyzed by using ray tracing and finite element analysis methods, and the influence of surface shape change of the semi-ellipsoidal mirror at 30 ℃ on optical characteristics is analyzed. Finally, the shape of the inner surface of the semi-ellipsoid mirror is measured by the three-coordinate measurement instrument, and the simulation results are verified. Experimental results show that: at 30 ℃, the root mean square (RMS) of the deformation of the semi-ellipsoidal mirror after removing ellipsoid deformation is 2.15 μm, the irradiation uniformity obtained by using a Φ15 mm blackbody radiation source is 61%, the energy utilization is 7.6%, and the RMS is 5.75 μm measured by the three-coordinate measuring instrument. This study provides a new way to measure high-temperature optical parameters of materials.
Acta Optica Sinica
- Publication Date: Mar. 23, 2021
- Vol. 41, Issue 6, 0608002 (2021)
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