调制传递函数是红外遥感卫星像质评价的核心参数,但其在轨检测面临靶标温差稳定性不足与数据处理复杂两大挑战。提出一种基于三线靶标与温阶靶标协同的在轨调制传递函数(modulation transfer function,MTF)直接检测方法,通过靶标设计与...调制传递函数是红外遥感卫星像质评价的核心参数,但其在轨检测面临靶标温差稳定性不足与数据处理复杂两大挑战。提出一种基于三线靶标与温阶靶标协同的在轨调制传递函数(modulation transfer function,MTF)直接检测方法,通过靶标设计与模糊PID(proportional-integralderivative)温控算法,实现靶标温度均匀性(<0.5℃)、稳定性(±0.6℃)与重复性(>99%)的良好表现。基于傅里叶光学理论与辐射传输模型,结合“物方-像方调制度分离”计算原理,从遥感影像中直接提取奈奎斯特频率处MTF值,避免了传统方法中大气因素、数值微分以及参数拟合误差等对MTF检测的影响,为高分辨率红外卫星定量化应用提供了高精度技术支撑。展开更多
采用中红外光谱(MIR)研究钨酸钠分子结构。钨酸钠分子红外吸收模式主要包括W—O键不对称伸缩振动模式和W—O键对称伸缩振动模式等。采用变温中红外光谱(TD-MIR)研究温度对钨酸钠分子结构的影响。在303~573 K的温度范围内,随着测定温度...采用中红外光谱(MIR)研究钨酸钠分子结构。钨酸钠分子红外吸收模式主要包括W—O键不对称伸缩振动模式和W—O键对称伸缩振动模式等。采用变温中红外光谱(TD-MIR)研究温度对钨酸钠分子结构的影响。在303~573 K的温度范围内,随着测定温度的升高,钨酸钠分子ν_(as-W-O)和ν_(s-W-O)对应的红外吸收频率和强度均发生明显的改变。以ν_(as-W-O)和ν_(s-W-O)为研究对象,采用二维中红外光谱(2D-MIR)研究钨酸钠分子的热变性。研究发现,在303~373、383~463、473~573 K 3个温度区间,钨酸钠分子主要官能团(ν_(as-W-O)和ν_(s-W-O))对热敏感程度及变化快慢顺序都存在较大差异,并进一步进行了热变性机理的研究。本研究拓展了中红外光谱技术(MIR、TD-MIR和2D-MIR)在重要的稀有金属盐(钨酸钠)分子结构及热变性领域的研究范围。展开更多
Electro-Optic Sampling(EOS)detection technique has been widely used in terahertz science and tech⁃nology,and it also can measure the field time waveform of the few-cycle laser pulse.Its frequency response and band lim...Electro-Optic Sampling(EOS)detection technique has been widely used in terahertz science and tech⁃nology,and it also can measure the field time waveform of the few-cycle laser pulse.Its frequency response and band limitation are determined directly by the electro-optic crystal and duration of the probe laser pulse.Here,we investigate the performance of the EOS with thin GaSe crystal in the measurement of the mid-infrared few-cycle la⁃ser pulse.The shift of the central frequency and change of the bandwidth induced by the EOS detection are calcu⁃lated,and then the pulse distortions induced in this detection process are discussed.It is found that this technique produces a red-shift of the central frequency and narrowing of the bandwidth.These changings decrease when the laser wavelength increases from 2μm to 10μm.This work can help to estimate the performance of the EOS de⁃tection technique in the mid-infrared band and offer a reference for the related experiment as well.展开更多
文摘调制传递函数是红外遥感卫星像质评价的核心参数,但其在轨检测面临靶标温差稳定性不足与数据处理复杂两大挑战。提出一种基于三线靶标与温阶靶标协同的在轨调制传递函数(modulation transfer function,MTF)直接检测方法,通过靶标设计与模糊PID(proportional-integralderivative)温控算法,实现靶标温度均匀性(<0.5℃)、稳定性(±0.6℃)与重复性(>99%)的良好表现。基于傅里叶光学理论与辐射传输模型,结合“物方-像方调制度分离”计算原理,从遥感影像中直接提取奈奎斯特频率处MTF值,避免了传统方法中大气因素、数值微分以及参数拟合误差等对MTF检测的影响,为高分辨率红外卫星定量化应用提供了高精度技术支撑。
文摘采用中红外光谱(MIR)研究钨酸钠分子结构。钨酸钠分子红外吸收模式主要包括W—O键不对称伸缩振动模式和W—O键对称伸缩振动模式等。采用变温中红外光谱(TD-MIR)研究温度对钨酸钠分子结构的影响。在303~573 K的温度范围内,随着测定温度的升高,钨酸钠分子ν_(as-W-O)和ν_(s-W-O)对应的红外吸收频率和强度均发生明显的改变。以ν_(as-W-O)和ν_(s-W-O)为研究对象,采用二维中红外光谱(2D-MIR)研究钨酸钠分子的热变性。研究发现,在303~373、383~463、473~573 K 3个温度区间,钨酸钠分子主要官能团(ν_(as-W-O)和ν_(s-W-O))对热敏感程度及变化快慢顺序都存在较大差异,并进一步进行了热变性机理的研究。本研究拓展了中红外光谱技术(MIR、TD-MIR和2D-MIR)在重要的稀有金属盐(钨酸钠)分子结构及热变性领域的研究范围。
基金Supported by the National Natural Science Foundation of China(12064028)Jiangxi Provincial Natural Science Foundation(20232BAB201045).
文摘Electro-Optic Sampling(EOS)detection technique has been widely used in terahertz science and tech⁃nology,and it also can measure the field time waveform of the few-cycle laser pulse.Its frequency response and band limitation are determined directly by the electro-optic crystal and duration of the probe laser pulse.Here,we investigate the performance of the EOS with thin GaSe crystal in the measurement of the mid-infrared few-cycle la⁃ser pulse.The shift of the central frequency and change of the bandwidth induced by the EOS detection are calcu⁃lated,and then the pulse distortions induced in this detection process are discussed.It is found that this technique produces a red-shift of the central frequency and narrowing of the bandwidth.These changings decrease when the laser wavelength increases from 2μm to 10μm.This work can help to estimate the performance of the EOS de⁃tection technique in the mid-infrared band and offer a reference for the related experiment as well.
