2024

• Record 181 of
  
  Title:An innovative 16-bit projection display based on quaternary hybrid light modulation
  
  Author(s):Pan, Yue(1,2); Cao, Yajie(1); Xu, Liang(3); Hu, Motong(1); Jiang, Qing(4); Li, Shuqin(4); Lu, Xiaowei(1)
  Source: Optics and Lasers in Engineering  Volume: 178  Issue:   DOI: 10.1016/j.optlaseng.2024.108171  Published: July 2024  
  Abstract:Conventional spatial light modulators (SLM) can only be used for projecting 8-bit or 10-bit images at normal frame rate. Therefore, commercial high dynamic range (HDR) displays typically focus on boosting the contrast while neglecting to raise the bit-depth. Existing methods for high bit-depth display generally rely on stacking two SLMs to modulate the outgoing beam twice, namely multiplicative modulation, resulting in many troubles such as low optical efficiency, difficulty in pixel-level alignment, and complex image rendering algorithm. In this paper, an innovative quaternary hybrid light modulation (QHLM) based projection display is proposed and realized. By illuminating two parallel digital micro-mirror devices (DMDs) with different light intensities, the quaternary digit-planes (QDs) with four gray levels are able to be modulated rapidly. Aiming at this ability, the quaternary pulse width modulation (QPWM) is incorporated with the quaternary light-intensity modulation (QLM) to fundamentally improve the modulation efficiency compared to the binary light modulation mode. Furthermore, the quaternary digit-plane decomposition (QDD) based image splitting algorithm is adopted to split a high bit-depth image into two images that drive two DMDs respectively. The prototype is designed and built to verify the feasibility of the QHLM based projection display. The experimental results demonstrate that the prototype can project 16-bit images at 220 fps. Through additive modulation of two DMDs in parallel, the QHLM entirely avoids the drawbacks of multiplicative modulation. As a completely different technology, the QHLM has a great potential for HDR projection applications. © 2024 Elsevier Ltd
  Accession Number: 20241215789270
• Record 182 of
  
  Title:Effects of Black Silicon Surface Morphology Induced by Femtosecond Laser on Absorption and Photoelectric Response Efficiency
  
  Author(s):Zhang, Xiaomo(1,2); Li, Weinan(1,2); Jin, Chuan(1,2); Cao, Yi(1,2); Liu, Feng(4); Wei, Na(1,2); Wang, Bo(1,2); Zhou, Rundong(1,2); Zhu, Xiangping(1,2,3); Zhao, Wei(1,2)
  Source: SSRN  Volume:   Issue:   DOI:   Published: February 14, 2024  
  Abstract:In this study, black silicon was achieved by femtosecond laser etching the silicon wafer surface. Surface microstructures of black silicon were closely related to laser etching parameters such as energy density. Changing laser energy density. can significantly alter the shape of microstructures including the base radius ([[EQUATION]]) and height ([[EQUATION]]) of the parabolic cone. The relationship between the base radius ([[EQUATION]]) , height (h) and the reflection, transmission, and absorption of black silicon in the range of 260 nm to 1460 nm was simulated using the finite-difference time-domain method (FDTD). The results indicated that [[EQUATION]] was directly proportional to the absorbances, while [[EQUATION]] presented an inverse proportion to the absorbances. And [[EQUATION]] ( represents the tape angle of the microstructure) demonstrated a direct proportionality to the average absorbances. With different etching energy density the characterization was performed on the surface morphology parameters, absorbance, and photoelectric response efficiency of black silicon. The results showed that the change in absorbance was positively correlated with [[EQUATION]], but the correlation between photoresponse efficiency and [[EQUATION]] was not obvious. Raman spectroscopy characterization revealed a positive correlation between the peak intensity change at the Si-I (520 [[EQUATION]]) and the photoelectric response efficiency. And the peak intensity at Si-I (520 [[EQUATION]]) decreaseed with increasing etching energy density, indicating the introduction of more lattice defects, which weakened the efficiency of charge carrier transport. This study revealed the influence mechanism on the absorbance and energy density of black silicon with small changes of microstructure, which can provide a valuable reference for further optimization of the energy density of black silicon. © 2024, The Authors. All rights reserved.
  Accession Number: 20240076398
• Record 183 of
  
  Title:Radiative Transfer Characteristics of the 1.27 um O2(a1Δg) Airglow in Limb-Viewing
  
  Author(s):Wang, Dao-Qi(1); Wang, Hou-Mao(2); He, Wei-Wei(1); Hu, Xiang-Rui(1); Li, Juan(3); Li, Fa-Quan(4); Wu, Kui-Jun(1)
  Source: Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis  Volume: 44  Issue: 4  DOI: 10.3964/j.issn.1000-0593(2024)04-1088-10  Published: April 2024  
  Abstract:Because the 1.27 um O2(a1Δg)) airglow radiation has the advantages of strong radiation signal, large space span and weak self-absorption effect, it is an important target source for near-space atmospheric remote sensing. In addition, it has important scientific significance and application value, such as research on the dynamics and thermal characteristics of the middle and upper atmosphere, global greenhouse gas detection, and three-dimensional tomography of ozone concentration. Firstly, based on the photochemical model of O2(a1Δg), the generation and annihilation mechanisms of O2(a1Δg) airglow were studied. The volume emission rate profile of O2(a1DELg) airglow was calculated on this basis. Based on the spectral intensity and Einstein coefficients given by HITRAN, two methods for calculating the spectral distribution of O2(a1Δg) airglow were proposed. Using the latest molecular spectral parameters, photochemical reaction rate constant and F 10.7 solar ultraviolet flux, combined with the volume emission rate profile information of O2(a1Δg) airglow calculated by photochemical reaction model. The radiative transfer theoretical model of the 1. 27 um O2(a1Δg) airglow in limb-viewing was developed by using a line-by-line integration algorithm. The influence of the self-absorption effect on the spectral intensity of airglow radiation at different tangent heights is analyzed. Then, the O2(a1Δg) airglow radiation spectrum of the target layer is obtained by processing the airglow radiation of the O2 molecule near the infrared atmospheric band measured by scanning imaging absorption spectrometer for atmospheric chartography (SCIAMACHY) under the limb-viewing by onion peeling algorithm. Spectral integration algorithm is used to retrieve the volume emission rate profile of O2(a1Δg)) airglow. Finally, the reliability and rationality of the radiative transfer theoretical model of the 1. 27 jim O2(a1Δg)) airglow in limb-viewing is verified by comparing the radiation spectrum and the volume emission rate profile obtained from the theoretical calculation and retrieval of the SCIAMACHY instrument. Regarding the comparison results, factors that contribute to the limb radiation intensity and volume emission rate of O2(a1Δg) airglow are analyzed. Analyses show that theoretical calculations agree with measured satellite results in the altitude region above 50 km. However, the deviation between the two increases gradually with the decrease of altitude because the satellite remote sensing in the middle and low altitude regions are seriously affected by the self-absorption effect and atmospheric scattering effect in limb-viewing. Additionally, compared with the spectral line intensity parameter given by the HITRAN database, the O2(a1Δg)) airglow limb radiation model based on Einstein coefficients is more consistent with the measured satellite results. Establishing the radiative transfer theoretical model of the 1. 27 um O2(a1Δg) airglow in limb-viewing provides a theoretical foundation for atmospheric remote sensing in near space. © 2024 Science Press. All rights reserved.
  Accession Number: 20241515862842
• Record 184 of
  
  Title:A 85-Gb/s PAM-4 TIA With 2.2-mApp Maximum Linear Input Current in 28-nm CMOS
  
  Author(s):Ma, Shuaizhe(1); Yin, Zhenyu(1); Ran, Nianquan(1); Xia, Yifei(1); Yang, Ruixuan(1); Yu, Chuanhao(1); Xu, Songqin(1); Wang, Binhao(2); Qi, Nan(3); Zhang, Bing(1); Shi, Jingbo(4); Gui, Xiaoyan(1); Geng, Li(1); Li, Dan(1)
  Source: IEEE Solid-State Circuits Letters  Volume: 7  Issue:   DOI: 10.1109/LSSC.2024.3351683  Published: 2024  
  Abstract:This letter presents a 100-Gb/s CMOS PAM-4 transimpedance amplifier (TIA) with multimilliampere maximum linear input current. A low-noise high-linearity TIA architecture is proposed, leveraging the reconfigurable front-end (FE) TIA and the continuous time linear equalizer (CTLE) synced at multiple gain modes. Implemented in a 28-nm CMOS technology, the TIA achieves bandwidth of more than 24 GHz with transimpedance gain of 65 dB Ω, while showing an acrlong IRN current density of 10.4 pA/ √ Hz. The maximum linear input current reaches 2.2 mApp and the total harmonic distortion (THD) is less than 3% for an output swing of 600 mVpp, diff. The chip consumes power of 56 mW from 1.4 and 1.1-V supply. © 2018 IEEE.
  Accession Number: 20240315388252
• Record 185 of
  
  Title:Research of laser atmospheric propagation of large-aperture antenna measurement
  
  Author(s):Zhang, Xuan(1); Gao, Ming(1); Wang, Hu(1,2,3,4,5); Lin, Shangmin(2,3,4); Jin, Yu(2,3); Lai, Yunqiang(2,3); Lv, Hong(1); He, Wenlong(2,3)
  Source: Proceedings of SPIE - The International Society for Optical Engineering  Volume: 13070  Issue:   DOI: 10.1117/12.3021213  Published: 2024  
  Abstract:Laser measurement technology is widely used in antenna main reflector and subreflector deformation or pose measurement. Based on the laser measurement technology, atmospheric turbulence caused by the atmospheric characteristics or the convergence effect of the antenna itself will affect the refractive index disturbance during laser propagation, which affects the accuracy of the laser measurement of the antenna deformation or pose. In order to solve the problem of laser atmospheric propagation deflection caused by atmospheric turbulence on the near-ground of a large-aperture antenna, firstly, this paper decomposes the laser atmospheric propagation path into multiple isotropic air layers, calculates the atmospheric refractive index of each air layer, obtains the atmospheric refractive index of the whole laser propagation path through curve fitting methods, and then assesses the laser deflection. Secondly, the turbulence intensity under sunny daytime and cloudy nighttime are evaluated, the laser spot position deviation is compared and analyzed, and the matching relationship among turbulence intensity, theoretical deviation of the laser spots, and actual spot deviation is obtained. Finally, the deflection of laser atmospheric propagation is fitted and calculated by measuring environmental data matched to the actual experimental data of the Nanshan 26m radio telescope antenna, which verifies the effectiveness and feasibility of the proposed method. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.
  Accession Number: 20241315797460
• Record 186 of
  
  Title:Circularly polarized RABBITT applied to a Rabi-cycling atom
  
  Author(s):Liao, Yijie(1); Olofsson, Edvin(2); Dahlström, Jan Marcus(2); Pi, Liang-Wen(3); Zhou, Yueming(1); Lu, Peixiang(1,4)
  Source: Physical Review A  Volume: 109  Issue: 4  DOI: 10.1103/PhysRevA.109.043104  Published: April 2024  
  Abstract:We utilize the reconstruction of attosecond beating by interference of two-photon transitions (RABBITT) technique to study the phase of a Rabi-cycling atom using circularly polarized extreme ultraviolet and infrared fields, where the infrared field induces Rabi oscillations between the 2s and 2p states of lithium. Autler-Townes splittings are observed in sidebands of the photoelectron spectra and the relative phases of outgoing electron wave packets are retrieved from the azimuthal angle. In this RABBITT scheme, more ionization pathways beyond the usual two-photon pathways are required. Our results show that the polar-angle-integrated and polar-angle-resolved RABBITT phases have different behaviors when the extreme ultraviolet and infrared fields have co- and counter-rotating circular polarizations, which are traced back to the different ionization channels according to the selection rules in these two cases and their competition relying on the propensity rule in laser-assisted photoionization. © 2024 American Physical Society.
  Accession Number: 20241515854295
• Record 187 of
  
  Title:Single line of sight frame camera based on the RadOptic effect of ultrafast semiconductor detector
  
  Author(s):Liu, Yiheng(1,2,3); He, Kai(1); Yan, Xin(1); Gao, Guilong(1); Du, Wanyi(1); Shang, Yang(1); Wang, Gang(1); Wang, Tao(1); Zhang, Jun(4); Tian, Jinshou(1,3); Tan, Xiaobo(4)
  Source: Optics and Lasers in Engineering  Volume: 175  Issue:   DOI: 10.1016/j.optlaseng.2024.108029  Published: April 2024  
  Abstract:A new optical beam splitting method is proposed, based on which the optical frame camera capable of capturing multiple frames in a single exposure is designed and experimentally verified. The operation of the frame camera is based on an ultra-fast response semiconductor detector. It is equipped with an optical beam splitter and an optical imaging module. The ultrafast semiconductor detector receives an optical pulse that produces a transient refractive index change, and ultrafast physical processes are recorded by diffracting the probe laser through the transient phase grating. The interaction of an X-ray pulse with a semiconductor detector to produce a phase grating is simulated, based on the Monte Carlo method. The optical beam splitting mode separates a laser into two optical pulses with a certain time difference in the direction of polarization perpendicular to each other. The imaging module filters the diffracted probe laser in the spectral plane and then images multiple frames. The frame camera was used to record the temporal and spatial distribution characteristics of femtosecond laser pulses with a temporal resolution of 4.1 ps. This frame camera has great potential and value for applying to experimental studies of inertial confinement fusion. © 2024 Elsevier Ltd
  Accession Number: 20240315382269
• Record 188 of
  
  Title:A Comprehensive Equivalent Circuit Model of Silicon Microring Modulators for Photonics-Electronics Codesign
  
  Author(s):Bao, Shenlei(1); Ma, Yingjie(2); Xue, Jintao(1); Wu, Jinyi(1); Qi, Nan(2); Wang, Binhao(1)
  Source: Journal of Lightwave Technology  Volume:   Issue:   DOI: 10.1109/JLT.2024.3382091  Published: 2024  
  Abstract:Silicon microring modulators have huge potential for applications in co-packaged optics (CPO) and optical I/O (OIO) owing to the superior bandwidth, small footprint, and inherent wavelength multiplexing characteristics. To enable efficient and robust optical transceiver systems, codesign and cosimulation environments are essential for optimization of photonic devices, transceiver circuitry and electronic-photonic integrated circuits (EPIC). We introduce a comprehensive equivalent circuit model for single- and dual-segment silicon microring modulators (MRMs), which accurately capture the device behavior during high-speed modulation. This model includes electrical parasitics, nonlinear optical steady state and dynamics, and thermo-optic effects. Model parameters are extracted by curve fitting MRM optical transmission spectrum and small signal characteristics. The simulated eye diagrams exhibit excellent alignment with the measured eye diagrams at data rates of 80Gb/s and 106Gb/s. A cosimulation environment with a MRM driver in 28nm CMOS and a MRM in 130nm silicon photonics is demonstrated on an electronics design automation (EDA) platform. An optical eye diagram at a data rate of 212Gb/s PAM8 is successfully achieved by optimizing the driver equalizer and the MRM two segment ratio. Then an EPIC with photonics-electronics closedloop feedback control algorithm is demonstrated, achieving a significantly larger eye opening after thermal tuning, thanks to the accurate equivalent circuit model of the MRM. IEEE
  Accession Number: 20241415849026
• Record 189 of
  
  Title:Pakistan's 2022 floods: Spatial distribution, causes and future trends from Sentinel-1 SAR observations
  
  Author(s):Chen, Fang(1,2,3); Zhang, Meimei(1,2); Zhao, Hang(4); Guan, Weigui(1,2,3); Yang, Aqiang(1,2)
  Source: Remote Sensing of Environment  Volume: 304  Issue:   DOI: 10.1016/j.rse.2024.114055  Published: April 1, 2024  
  Abstract:Floods are a great threat to Pakistan with increasing concern. As the consequences of increased extreme weather related to climate change, Pakistan experiences severe floods almost every year. This study aims to explore and analysis the actual inundated situation, magnitude, the possible causes of the 2022 devastating floods, and future trends. We presented an enhanced nationwide flood mapping method and compared with other pixel-based image processing techniques including active contours and change detection. These algorithms were applied to Sentinel-1 Ground Range Detected (GRD) Synthetic Aperture Radar (SAR) imagery (10 m spatial resolution) with various land types and inundation scenarios in Pakistan, and were evaluated using other reference flood products. Accuracy evaluation analysis demonstrated that our algorithm has high robustness and accuracy, with the overall accuracy (OA) higher than 0.83 and critical success index (CSI) up to 0.91, and is suitable for automated flood monitoring in near real time. Nearly one-third of the lands were flooded in 2022, and more than half were inundated croplands. Punjab and Sindh provinces were the most severely affected regions, with the proportions of inundated area in 2022 (21.26% and 20.55%) nearly twice of that in 2010 (11.40% and 12.70%), indicating an intensified flooding trend. Analysis of possible influential factors showed that the intense and cumulative rainfall during the monsoon season (June to August) was the major cause of the 2022 flood event. Although the snow melted rapidly in June (the average change in snow depth is ∼10 mm), the overall ablation contributed insignificant amount to the flood water. The glacial lake outburst floods (GLOFs) induced by abnormal April–May heatwave provide water flowed into the tributaries of the Indus River, but are difficult to spread for thousands of kilometers from mountains to the plain downstream. The combination of the intrinsic arid climate and extreme floods exacerbate the already severe situation. © 2024 Elsevier Inc.
  Accession Number: 20240915643476
• Record 190 of
  
  Title:Dynamic Range Study of Microchannel Plate Photomultiplier Tubes under Visible Light Pulse Input
  
  Author(s):Wei, Jianan(1,2); Liu, Hulin(2); Chen, Ping(2,3); Li, Yang(4); Li, Kuinian(2); Wei, Yonglin(2); He, Luanxuan(1,2); Zhao, Xinnan(1,2); Sai, Xiaofeng(2); Liu, Deng(5); Tian, Jinshou(2,3); Zhao, Wei(2,3)
  Source: Guangzi Xuebao/Acta Photonica Sinica  Volume: 53  Issue: 2  DOI: 10.3788/gzxb20245302.0204001  Published: February 2024  
  Abstract:Microchannel Plate Photomultiplier Tube（MCP-PMT），as a high-performance photodetector，has been widely used in various detection experiments in recent years. In previous studies，people mainly focused on improving the sensitivity and temporal resolution of optoelectronic detection devices，while ignoring the key factor of high linearity. With the continuous development of the demand for large dynamic detection，in-depth research and development of MCP-PMT with large dynamic range has become an urgent need for current research.The dynamic range of MCP-PMT is related to many factors，such as the intensity and frequency of input visible light，the material of the microchannel board，and the voltage values applied to each part of MCP-PMT. This article mainly starts from two aspects：the input light pulse frequency and the potential difference applied by the backend of MCP-PMT，and delves into the reasons why the output electrons of MCP-PMT deviate from normal linear multiplication. By combining theoretical analysis and experimental testing，the influence of the repetition frequency of pulse light signals and the potential difference between the second microchannel plate and the anode on the dynamic range of MCP-PMT was studied in detail. When the input light pulse width is 50 ns and the repetition frequency is 500 Hz，the maximum linear output of the anode can reach 2 V（i.e. 40 mA）；when the repetition frequency increases to 1 000 Hz，the linear deviation degree reaches more than 10% when the anode output is 1 V（i. e. 20 mA）；when the input light frequency further increases to 5 000 Hz and the anode output reaches 0.3 V（i. e. 6 mA），the degree of linear deviation has reached about 15%. As the electric potential difference between the second microchannel plate and the anode increases，the maximum linear output voltage of the anode shows fluctuating changes. When the electric potential difference between the second microchannel plate and the anode is around 200 V，the linear output voltage of the anode reaches its peak. As the electric potential difference increases，the linear output voltage of the anode begins to fluctuate，reaching the second peak at a electric potential difference of around 500 V. In this article，we investigated the influence of the frequency of pulse input light and the electric potential difference between the second microchannel plate and the anode on the dynamic range of MCP-PMT，and obtained two conclusions through experimental verification：1）As the pulse input frequency increases，the output voltage of MCP-PMT will detach from the linear region earlier. 2）As the potential difference between MCP2 and the anode increases，the maximum linear output voltage of MCP-PMT does not simply vary monotonically，but exhibits a constantly fluctuating trend in resistance. On this basis，further exploration was conducted on the factors that constrain the dynamic range of MCP-PMT，namely insufficient wall charge supplementation and interference from space charge effects. When the frequency of the input pulse is high，the constraint on the dynamic range of MCP-PMT is mainly related to the former；when the electric potential difference between the second microchannel plate and the anode increases，due to the complex situation of a large number of secondary electrons transferring between the plates to the anode，the dynamic range will be affected by the space charge effect and cannot be directly proportional to the electric field strength. © 2024 Chinese Optical Society. All rights reserved.
  Accession Number: 20240715561760
• Record 191 of
  
  Title:Spectral domain characteristics of partially coherent illumination on grating imaging system
  
  Author(s):Jing, Xinyi(1); Hu, Xiaoying(1); Xu, Liang(2); Liu, Weiguo(1); Hanson, Steen G.(3); Takeda, Mitsuo(1,4); Wang, Wei(1,5)
  Source: Proceedings of SPIE - The International Society for Optical Engineering  Volume: 13070  Issue:   DOI: 10.1117/12.3013409  Published: 2024  
  Abstract:The grating imaging system has the advantages of high resolution, high sensitivity and strong anti-interference ability, and has been widely used in machine vision, biomedicine and imaging spectroscopy and other fields. The coherence and polarization properties of the light field have different effects on the grating imaging system. This paper studies the polarization system of the grating illuminated by partially coherent light based on the unified theory of polarization and coherence. The experiment is carried out using a sinusoidal amplitude grating of 20 lines per mm. The experimental results show that when the coherence is fixed, as the normalized intrinsic frequency of the grating increases, the second harmonic disappears, leaving only the direct current (DC) component and the first harmonic component, which is consistent with the theoretical result. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.
  Accession Number: 20241315797429
• Record 192 of
  
  Title:Error Correction for Cell Calibration of SO2 Ultraviolet Camera
  
  Author(s):Zhang, Huiliang(1); Li, Faquan(2); Li, Juan(3); Wang, Houmao(4); Zhang, Zihao(1); Guo, Jianjun(1); Wu, Kuijun(1); He, Weiwei(1)
  Source: Guangxue Xuebao/Acta Optica Sinica  Volume: 44  Issue: 6  DOI: 10.3788/AOS230886  Published: March 2024  
  Abstract:Objective Industrial chimneys, ship exhaust, and volcanic eruption processes can emit large amounts of harmful SO2 into the atmosphere, causing serious pollution to the environment. The development of effective SO2 monitoring tools can provide a strong guarantee for atmospheric environmental management. In recent years, SO2 ultraviolet (UV) cameras have been rapidly developed and widely applied by virtue of their high spatio-temporal resolution, high detection sensitivity, and two-dimensional detection imaging capability. Due to the limitation of physical principles, the initial amount measured by the SO2 UV camera is the optical thickness of SO2 gas, which needs to be retrieved into a concentration image with the help of calibration curves, and the accuracy of calibration curves directly affects the accuracy of SO2 concentration results. Cell calibration and differential optical absorption spectroscopy (DOAS) calibration are two main methods for obtaining calibration curves. In terms of equipment cost, easy operation, and system stability, the cell method is significantly better than the DOAS method, but its calibration accuracy is seriously affected by the light dilution effect, reflections on the windows of the calibration cell and filter, and aerosol scattering factors. Additionally, with the rising detection distance, the above factors, especially the influence of the light dilution effect, become increasingly more serious. To improve the calibration accuracy of the cell method, we research the calibration error correction method to address the practical problem of inaccurate cell method calibration in remote SO2 monitoring. Methods In practice, since the factors affecting the accuracy of the cell method are mainly from the light dilution effect, window reflection, and the scattering of aerosols, it is necessary to correct each of these factors. The specific method is as follows. Firstly, the image correction method (ICM) is proposed for correcting the light dilution effect, and the extinction coefficient is obtained by fitting the intensity information of the measurement points at different distances in the UV camera images. Additionally, the optical thickness image of the cell at the measured distance is calculated by the extinction coefficient, and then the calibration curve with the correction of the light dilution effect is obtained. Then, based on the analysis of window reflection and aerosol scattering effect, the influence of the reflection effect and scattering characteristics on the calibration results are quantified. Finally, the calibration curves with the correction of light dilution effect and scattering characteristics are calculated by combining the above influencing factors. Results and Discussions Based on the Etna volcanic plume image data captured by Professor Jonas Gliß from the Norwegian Air Research Institute using a SO2 ultraviolet camera, the Etna volcanic plume SO2 concentration image is retrieved by calibration curves before and after the correction of the light dilution effect. The results are compared with the retrieval results of the DOAS calibration curve, and the results show that the correction of the light dilution effect can reduce the differences between the cell method and the DOAS method from 59.0% to 31.3%, which verifies the effectiveness of ICM in correcting light dilution effect. After correction for reflection and scattering effects, the difference between the cell method and the DOAS method is reduced to 7%. The cell method and DOAS method show good agreement in the time domain after correction, and the fitting curve slope of the primary function of the calibration results is 0.924, with a goodness-of-fit of 0.998. Conclusions The results show that the proposed error correction method for cell calibration of the SO2 UV camera can improve the calibration curve accuracy. The fitting accuracy of the extinction coefficient and the measurement accuracy of the filter reflectance and the quartz window directly affect the accuracy of the calibration curve. The error analysis results show that a 10% shift in the extinction coefficients ΕA and ΕB obtained from channels A and B fitting will cause an error of 8.44% and 13.57% for SO2 column density retrieval respectively, while a 10% shift in background light intensity will result in an error of 4.98% for SO2 column density retrieval. Additionally, a 10% error in the filter reflectance and the quartz window will result in a 6.26% and 1.95% shift in the SO2 column density respectively. Increasing the interval distance of sampling points and the number of sampling points can improve the fitting accuracy of the extinction coefficient. The high-resolution UV spectrometer ensures that the filter reflectance and the quartz window are accurately measured to control errors caused by the reflectance uncertainty. The proposed error correction method for calibration curves solves the limitation that the cell method cannot be applied to monitor the plumes at long distances and high carbon black concentrations, which is important for better applications of SO2 UV cameras in volcanoes, ships, and industrial chimneys. © 2024 Chinese Optical Society. All rights reserved.
  Accession Number: 20241215789360