红外紫外双色光谱的产生

本文给出了在红外光谱多外利用热受激后的原子材料产生紫外光谱的方法。文中给出了计算数据和实验结果。     

高光谱遥感器的光谱定标

高光谱遥感器光谱性能参数的准确定标是高光谱遥感器数据定量应用的基本前提。本文基于单色准直光标定法对高光谱遥感器进行了光谱性能参数定标,通过数据采集软件及数据处理软件对高光谱遥感器光谱性能参数定标数据进行了分析。分析结果显示:定标测试的重复性在1 h内小于0.2 nm,在20 h内小于0.35 nm。光谱定标结果表明:高光谱遥感器的平均光谱分辨率为4.94 nm,且各高光谱遥感器空间维光谱分辨率均小于5 nm,典型谱段的平均带宽均在6 nm左右。     

广义二维相关光谱技术及其应用

广义二维相关光谱技术目前逐渐成为光谱分析中广泛应用的研究方法,综述了其历史发展、基本原理、获取谱图方法、数学计算过程、谱图性质及其解释规则,并介绍了二维红外、近红外、拉曼和荧光光谱相关光谱技术在各个领域中的应用,展望了广义二维相关光谱技术的发展趋势。     

基于光谱分类的端元提取算法研究

目前成熟的端元提取算法是基于单形体几何学的像元纯度指数(PPO)算法,N-FINDR,VCA等算法.这些算法从图像所有像元中提取纯光谱,具有提取速度慢、精度不高的缺点;部分算法需要进行光谱降维,不利于小目标信息的提取.该文提出先利用基于空间特征的光谱分类算法进行分类,将格个图像划分成空间相邻、光谱相似的若干类,每一类的...     

多孔硅的时间延迟光谱

利用时间延迟光谱技术测量了多孔硅的发光光谱. 实验结果表明,多孔硅的发光是复杂的动力学发光弛豫过程,时间延迟光谱测量技术在研究复杂动力学发光过程方面比稳态光谱测量方法更有效.     

TixY1-xBa2Cu3O7-δ超导体的红外、远红外光谱

本文报道了Ti_xY_1-xBa₂Cu₃O_7-δ(x=0.2和0.4)在4.2—300K的红外、远红外光谱。在50—360cm^-1波段内发现七个反射峰。它们分别与Ba,Cu,O离子团,Y,O离子团。Ti,O离子团,以及Cu—O键的振动有关,对于x=0.2的样品,存在两个反转结构。对于x=0.4的样品,则仅发现一个反转结构。在红外光谱中观察到六个反对峰和三个吸收峰,它们的强度大多随Ti含量的增加而增强。与Y₁Ba₂Cu₃O_7-δ的光谱结果比校,讨论了声子峰及反转结构的物理起因。 关键词：     

基于光谱靶标的光学遥感器退化特性在轨评估方法研究

多光谱遥感器在轨运行期间,受化学分子污染、发射振动、宇宙辐射等因素的影响,其光谱响应特性会发生变化,使目标物理量的测量值产生偏差,且不能用辐射定标进行校正,影响数据产品序列的一致性。提出了一种基于光谱靶标的光谱响应退化特性在轨评估方法,通过建立响应函数退化模型,并利用光谱靶标反射率在检测波段内呈非线性变化的特性来实现对光谱响应函数退化情况的定量化评估。模拟仿真与外场实验结果初步验证了本文方法的有效性,该方法在提高辐射定标精度和优化遥感器设计等方面有重要意义。     

塞曼调制磁旋转激光光谱方法

首次在可见光波段采用塞曼调制磁旋转激光光谱技术有效地将磁旋转信号（ｎ＋，－ｎ－）从激光本底以及高阶磁旋转信号中分离出来，因而有非常高的测量灵敏度与信噪比以及无吸收本底，同时又可以抑制高转动量子态的跃迁谱线，减少谱线重叠现象，非常适合许多自由基分子的测量。文中给出了这种光谱技术的理论分析，并以ＮＯ２分子作为检验对象，由理论模拟计算所得谱线的强度，线型和位相与实测结果符合较好，因此也可利用这种光谱方法     

塞曼调制磁旋转光谱技术在磁场测量中的应用

首次提出采用塞曼调制－磁旋转光谱技术制成ＮＯ２分子磁场计的可能性．并对不同进场下，ＮＯ２分子塞曼调制磁旋转光谱１６８４６．２０ｃｍ－１谱线强度进行了测量，提出了这种新型磁强计的设计原理，并阐述了该磁强计的特点．     

Emission Spectrum Property of Modulated Atom-Field Coupling System

The emission spectrum of a two-level atom interacting with a single mode radiation field in the case of periodic oscillation coupling coefficient is investigated.A general expression for the emission spectrum is derived.The numerical results for the initial field in pure number stare are calculated.It is found that the effect of the coupling coefficient modulation on the spectral structure is very obvious in the case of a low modulation frequency and larger amplitude when the initial field is vacuum,which is potentially useful for exploring a modulated light source.     

Emission Spectrum Property of Modulated Atom-Field Coupling System

The emission spectrum of a two-level atom interacting with a single mode radiation field in the case of periodic oscillation coupling coefficient is investigated. A general expression for the emission spectrum is derived. The numerical results for the initial field in pure number stare are calculated. It is found that the effect of the coupling coefficient modulation on the spectral structure is very obvious in the case of a low modulation frequency and larger amplitude when the initial field is vacuum, which is potentially useful for exploring a modulated light source.     

Nonequivalent spectra of unpaired electrons in field and frequency modulation

We report a difference in the spectral lineshapes of continuous-wave (CW) electron paramagnetic resonance (EPR) spectroscopy between field and frequency modulation. This finding addresses the long-standing question of the effect of modulation in EPR absorption. We compared the first-derivative EPR spectra at 1.1 GHz for lithium phthalocyanine crystals, which have a single narrow linewidth in the EPR absorption spectrum, using field and frequency modulation. The experimental findings suggest that unpaired electrons have different behaviors under perturbation due to field and frequency modulation.     

斯塔克调制—电旋转激光光谱技术及其应用

采用斯塔克调制电旋转激光光谱技术将由偶然简并能级跃迁产生的电旋转信号从非简并能级跃迁中分离出来，因而简化了转动量子态的跃迁谱线，减少了谱线重叠现象，反映了分子能级受偶然简并斯塔克相互作用以及电四极相互作用的特性，非常适合那些转动谱线密集，微扰严重的多原子分子的光谱测量与分析。本文既给出了这种光谱技术的半经典理论模型，又运用微扰理论解释了用该技术所测的ＮＯ２分子的转动光谱的形成原因和它们的主要特征。     

Magnetic Faraday modulation spectroscopy of the 1–0 band of 14NO and 15NO

Magnetic rotation spectroscopy signals of the nitric oxide (NO) fundamental band near 5 μm have been observed and compared with calculated signals. This spectroscopic approach exploits magnetic field modulation in the Faraday configuration for very sensitive detection of NO. Line shapes and strengths of the Faraday signals depend on molecular parameters, like J and Ω quantum numbers of the transitions involved, and on experimental parameters, like pressure of the gas sample and applied external magnetic field strength. In this study we implemented a software model which provides a simulation of the complete v=1–0 Faraday spectrum of NO. The algorithm considers the magnetic field modulation, the collisional and Doppler broadening of the line shapes, and the line intensities of ¹⁴NO and ¹⁵NO fundamental band lines. Optimum values for pressure and magnetic field modulation for maximum sensitivity are given. Suitable spectral windows for simultaneous detection of ¹⁴NO and ¹⁵NO are discussed. Experimental data were obtained in the wavenumber region from 1840 to 1900 cm^?1 by means of a CO sideband laser and a quantum cascade laser. Comparison between calculated and observed signals shows excellent agreement.     

Reconstruction of the first-derivative EPR spectrum from multiple harmonics of the field-modulated continuous wave signal

Selection of the amplitude of magnetic field modulation for continuous wave electron paramagnetic resonance (EPR) often is a trade-off between sensitivity and resolution. Increasing the modulation amplitude improves the signal-to-noise ratio, S/N, at the expense of broadening the signal. Combining information from multiple harmonics of the field-modulated signal is proposed as a method to obtain the first derivative spectrum with minimal broadening and improved signal-to-noise. The harmonics are obtained by digital phase-sensitive detection of the signal at the modulation frequency and its integer multiples. Reconstruction of the first-derivative EPR line is done in the Fourier conjugate domain where each harmonic can be represented as the product of the Fourier transform of the 1st derivative signal with an analytical function. The analytical function for each harmonic can be viewed as a filter. The Fourier transform of the 1st derivative spectrum can be calculated from all available harmonics by solving an optimization problem with the goal of maximizing the S/N. Inverse Fourier transformation of the result produces the 1st derivative EPR line in the magnetic field domain. The use of modulation amplitude greater than linewidth improves the S/N, but does not broaden the reconstructed spectrum. The method works for an arbitrary EPR line shape, but is limited to the case when magnetization instantaneously follows the modulation field, which is known as the adiabatic approximation.     

Formulation of Zeeman modulation as a signal filter

The Bloch equation containing a Zeeman modulation field is solved analytically by treating the Zeeman modulation frequency as a perturbation. The absorption and dispersion signals at both 0 degrees and 90 degrees modulation phase are obtained. The solutions are valid to first order in the modulation frequency, but are otherwise valid for any value of modulation amplitude or microwave amplitude. A first order treatment of modulation frequency is shown to be a valid approximation over a wide range of typical experimental EPR conditions. The solutions derived from the Bloch equation suggest that the effect of over-modulation on first and second harmonic EPR spectra can be formulated as a mathematical filter that smoothes and broadens the under-modulated signal. The only adjustable filter parameter is a width that is equivalent to the applied peak-to-peak modulation amplitude. The true spin-spin and spin-lattice relaxation rates are completely determined from the under-modulated spectrum. The filters derived from the analytic solutions of the Bloch equation in the linear limit of modulation frequency are tested against numerical solutions of the Bloch equation that are valid for any modulation frequency to show their applicability. The filters are further tested using experimental EPR spectra. Experimental under-modulated spectra are mathematically filtered and compared with the experimental over-modulated spectra. The application of modulation filters to STEPR spectra is explored and limitations are discussed.     

超低频调制光缔合光谱的实验研究

通过激光冷却技术在磁光阱中俘获原子数约107,温度约200 μK,直径约400 μm的超冷铯原子,利用超冷铯原子光缔合方法制备了激发态的超冷铯分子。实验研究了光缔合光不同扫描速率对铯分子振转光谱分辨率的影响,发现光缔合光扫描速率较慢时,铯分子振转光谱分辨率较高。通过高灵敏的雪崩光电探测器探测冷原子荧光,获得了超冷铯分子第一激发态6S_1/2+6P_3/2离解限0-_g长程态高分辨振转光谱。为了实现受控拉曼光缔合制备超冷基态分子,光缔合激光频率需要锁定在原子-分子共振跃迁线,对超冷原子光缔合光谱进行了超低频波长调制,通过改变调制幅度和调制频率获得最优化的一阶微分信号,将该信号反馈回激光器,实现闭合环路稳频,满足了受控拉曼光缔合制备振转能级可控的基态分子的实验要求,该工作对研究受限空间中的超冷原子分子具有很重要的意义。