1 安徽农业大学信息与计算机学院, 安徽 合肥 230036
2 中国科学院合肥物质科学研究院安徽光学精密机械研究所, 中国科学院环境光学与技术重点实验室, 安徽 合肥 230031
可调谐半导体激光器是可调谐二极管激光吸收光谱（TDLAS）系统的重要器件之一，激光器输出波长的稳定性直接决定系统测量的准确性和稳定性，而注入电流和工作温度是激光器输出波长的主要控制因素。设计了激光器驱动控制电路，并利用PID控制实现激光器工作温度的恒温控制，不仅能提供高精度低噪声的注入电流，而且对激光器有完备的安全保护功能。首先对注入电流和温度控制进行了短期测试分析，随后将设计的电路应用于中心波长为1512 nm的激光器，开展了测试分析，对激光器的温度、电流调谐特性进行研究，并对激光器输出波长的稳定性进行了短期和长期测试。结果发现激光器输出波长的标准偏差为0.0002，满足TDLAS系统对激光器恒流恒温控制的要求，表明该驱动控制电路实现了对半导体激光器的高精度驱动控制。
光电子学 可调谐半导体激光器 电流驱动 TEC恒温控制 optoelectronics tunable semiconductor laser current drive TEC temperature control
1 安徽大学物质科学与信息技术研究院, 安徽 合肥 230601
2 中国科学院合肥物质科学研究院安徽光学精密机械研究所, 中国科学院环境光学与技术重点实验室, 安徽 合肥 230031
机动车运行工况复杂多变, 排放的尾气成分浓度范围跨度大。利用常规光学方法检测尾气中污染成分的浓度时, 由于受限于光学气池的结构固定和系统对光电微弱信号的检测极限, 因此待测气体的量程和精度范围都受到很大限制。基于朗博比尔定律, 在待测气体浓度变量上增加指数因子修正, 可以在不降低测量精度的同时, 实现尾气 CO、CO2 大量程检测。用标准气体对便携式机动车尾气检测装置进行标定实验, 结果表明, 传统的线性修正方法得到的 CO 拟合度为 0.988, CO2 拟合度为 0.998; 而增加了非线性修正因子后得到的 CO 拟合度为 0.999, CO2 拟合度为 0.999。进一步外场对比实验表明, 修正后的仪器测量结果与同类先进仪器的一致性较好, 柴油车实验拟合度为 0.93, 汽油车拟合度为 0.95, 验证了非线性修正方法的必要性和实用性。
光学检测 非线性修正 机动车尾气 碳氧化物 optical detection nonlinear correction vehicle exhaust carbon oxide 大气与环境光学学报
2022, 17(2): 241
1 中国电子科技集团公司第三十八研究所, 安徽 合肥 230088
2 中国科学院安徽光学精密机械研究所环境光学技术重点实验室, 安徽 合肥 230031
3 安徽省环境光学监测技术重点实验室, 安徽 合肥 230031
应用傅里叶变换红外光谱法进行在线工业窑炉高温气体监测时,湍流形成的噪声会影响光谱信噪比和浓度反演的精度。研究新的红外干涉信号-光谱转换的数据处理方法,该方法与传统傅里叶变换的光谱数据处理方法不同,它以零光程差为基准对齐干涉信号,实现多次扫描干涉信号的平均,同时采用复数窗函数与光谱数据卷积的方法来降低光谱旁瓣引起的光谱混叠程度。这种数据处理算法可以减小湍流噪声对气体浓度反演的影响,提高反演精度,减少计算量,提高光谱数据率。以叠加湍流的一氧化碳被动测量实验为例,分析了采用不同数据处理方法得到的光谱信噪比、光谱相关性和浓度反演结果。分析结果表明研究的信号数据处理方法在湍流噪声存在的在线检测中优于传统数据处理方法,采用新的数据处理方法得到的光谱更加精确(光谱相关性更好),气体反演的浓度也更准确,同时可减少系统计算量并缩短系统在线测量的响应时间,这对于在线监测气体浓度的准确性是至关重要的。
光谱学 傅里叶变换红外光谱法 湍流噪声 干涉信号 数据处理方法 光学学报
2021, 41(17): 1730001
红外与激光工程
2020, 49(3): 0305003
Author Affiliations
Abstract
1 Key Laboratory of Environmental Optics & Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China
2 Key Laboratory of Optical Monitoring Technology for Environment, Hefei 230031, China
3 Carinthian Tech Research, 9524 Villach, Austria
4 Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei 230031, China
5 State Key Laboratory of Pulsed Power Laser Technology, National University of Defense Technology, Hefei 230037, China
Spontaneous optical emission properties of laser-produced plasma during laser damage events at input and exit surfaces of fused silica were retrieved and compared. We show that plasma at the input surface is much larger in size and exhibits significantly higher electron number density and excitation temperature, even when smaller laser energy was used. This effect was attributed to the stronger laser–plasma coupling at the input surface. In addition, a strong continuum background containing three peaks at 1.3 eV, 1.9 eV, and 2.2 eV was observed at the exit surface, and possible origins for this effect are also discussed.
300.6365 Spectroscopy, laser induced breakdown 140.3330 Laser damage 140.3440 Laser-induced breakdown Chinese Optics Letters
2019, 17(12): 123002
Author Affiliations
Abstract
1 State Key Laboratory of Pulsed Power Laser Technology, National University of Defense Technology, Hefei 230037, China
2 Key Laboratory of Environmental Optics & Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China
Particle ejection is an important process during laser-induced exit surface damage in fused silica. Huge quantities of ejected particles, large ejection velocity, and long ejection duration make this phenomenon difficult to be directly observed. An in situ two-frame shadowgraphy system combined with a digital particle recognition algorithm was employed to capture the transient ejecting images and obtain the particle parameters. The experimental system is based on the principle of polarization splitting and can capture two images at each damage event. By combining multiple similar damage events at different time delays, the timeline of ejecting evolution can be obtained. Particle recognition is achieved by an adaptively regularized kernel-based fuzzy C-means algorithm based on a grey wolf optimizer. This algorithm overcomes the shortcoming of the adaptively regularized kernel-based fuzzy C-means algorithm easily falling into the local optimum and can resist strong image noises, including diffraction pattern, laser speckle, and motion artifact. This system is able to capture particles ejected after 600 ns with a time resolution of 6 ns and spatial resolution better than 5 μm under the particle recognition accuracy of 100%.
140.3330 Laser damage 160.6030 Silica 100.2000 Digital image processing Chinese Optics Letters
2019, 17(10): 101402
Author Affiliations
Abstract
1 School of Computer and Information, Hefei University of Technology, Hefei, Anhui 230009, P. R. China
2 Anhui Institute of Optics Fine Mechanics, Chinese Academy of Sciences, Hefei, Anhui 230031, P. R. China
As important components of air pollutant, volatile organic compounds (VOCs) can cause great harm to environment and human body. The concentration change of VOCs should be focused on in real-time environment monitoring system. In order to solve the problem of wavelength redundancy in full spectrum partial least squares (PLS) modeling for VOCs concentration analysis, a new method based on improved interval PLS (iPLS) integrated with Monte-Carlo sampling, called iPLS-MC method, was proposed to select optimal characteristic wavelengths of VOCs spectra. This method uses iPLS modeling to preselect the characteristic wavebands of the spectra and generates random wavelength combinations from the selected wavebands by Monte-Carlo sampling. The wavelength combination with the best prediction result in regression model is selected as the characteristic wavelengths of the spectrum. Different wavelength selection methods were built, respectively, on Fourier transform infrared (FTIR) spectra of ethylene and ethanol gas at different concentrations obtained in the laboratory. When the interval number of iPLS model is set to 30 and the Monte-Carlo sampling runs 1000 times, the characteristic wavelengths selected by iPLS-MC method can reduce from 8916 to 10, which occupies only 0.22% of the full spectrum wavelengths. While the RMSECV and correlation coefficient (Rc) for ethylene are 0.2977 and 0.9999ppm, and those for ethanol gas are 0.2977 ppm and 0.9999. The experimental results show that the iPLS-MC method can select the optimal characteristic wavelengths of VOCs FTIR spectra stably and effectively, and the prediction performance of the regression model can be significantly improved and simplified by using characteristic wavelengths.
Ambient air monitoring Fourier transform infrared spectra analysis variable selection interval partial least square Monte-Carlo sampling Journal of Innovative Optical Health Sciences
2019, 12(2): 1950005
1 中国科学院安徽光学精密机械研究所 中国科学院环境光学与技术重点实验室, 安徽 合肥 230031
2 中国科学技术大学, 安徽 合肥 230026
分析了温度、湿度、压力对预处理后尾气CO浓度测量的影响, 提出一种机动车尾气CO检测神经网络多环境因子在线修正算法, 首先采用尾气样本数据离线训练得到BP神经网络模型, 然后将实时测得的样品气温度、湿度、压力及小数吸收值代入到模型进行在线修正, 得到修正后CO浓度, 解决了NDIR传感器因环境变化所带来的测量误差影响。通过标样实验、模拟实验, 并和SEMTECH-EcoStar对比检测结果, 在样品气温度30～50 ℃、相对湿度25～40%、压力95～115 kPa、CO浓度0～0.2%范围内的最大相对偏差为4.8%。车载外场实验, 得到修正因子在0.8～1之间, 验证了方法的必要性和可靠性, 为机动车尾气的CO浓度的准确检测提供有效技术支持。
尾气CO检测 红外吸收 多环境因子 在线修正 BP神经网络 CO exhaust detection infrared absorption multiple environmental factors online correction BP neural network 红外与毫米波学报
2018, 37(6): 2018
1 中国科学院安徽光学精密机械研究所环境光学与技术重点实验室, 安徽 合肥 230031
2 中国科学技术大学, 安徽 合肥 230026
可调谐半导体激光吸收光谱技术(TDLAS)作为一种痕量气体精确检测的方法,已广泛应用于生活生产之中,该方法可通过积分吸光度与气体浓度的线性关系准确反演待测气体的浓度。环境变化和系统噪声等易造成吸光度曲线发生变形,故需对吸光度曲线进行非线性拟合,将其回归至Voigt模型。设计并搭建了基于TDLAS的CO实时在线监测系统,在此平台基础上,提出了一种三角替代Voigt线型单光谱积分吸光度的快速计算方法,并与高斯-埃尔米特方法进行比较。结果表明:三角替代方法浓度反演精度仅下降0.11%,平均计算耗时缩短84.19%;三角替代Voigt线型拟合方法以极小的精度损失,大幅提高了线型拟合的运算速度。
光谱学 可调谐半导体激光吸收光谱技术 Voigt线型拟合 三角替代方法 高斯-埃尔米特方法 光学学报
2018, 38(12): 1214001
1 中国科学院安徽光学精密机械研究所中国科学院环境光学与技术重点实验室, 安徽 合肥 230031
2 中国科学技术大学, 安徽 合肥 230026
被动傅里叶变换红外(FTIR)光谱技术具有远程操作、在线分析和不需要 红外光源等优点。基于此技术 分析了被动遥测轧钢加热炉内燃烧过程中高温一氧化碳(CO)气体浓度计算的相关理论与方法。针对加 热炉辐射光谱测量包含两层均质红外辐射传输介质的情况,提出了采用炉膛外壁控温改变遥测背景红外辐 射,从而获得炉内CO特征光谱的方法。基于轧钢过程中的燃烧工况进行了CO浓度模拟计算与分析,讨论了CO温 度测量误差对测量浓度反演精度的影响,为该技术的实际应用提供了参考数据及技术方案。
光谱学 被动遥测 傅里叶变换红外光谱 一氧化碳 高温 spectroscopy passive remote detection Fourier transform infrared spectroscopy carbon monoxide high temperature
