车载主动式红外夜视系统中带通滤光膜工艺研究

在车载主动式红外夜视系统中,为满足光学系统对滤光膜的要求,提出一种800～1000 nm带通滤光膜,以实现夜间大视觉范围、降低背景中杂散光干扰以及提高成像质量的要求。针对车载主动式红外夜视系统中带通滤光膜的参数要求,以薄膜材料应用技术为基础,优化、设计带通滤光膜系结构。采用OTFC-1300镀膜机制备薄膜,建立评价函数,通过牛顿迭代法优化薄膜结构,调节敏感膜层厚度,优化工艺,解决了实际镀制的薄膜通带中心区域透过率低,以及光谱曲线边缘起伏震荡大的问题,最终制作了光学性能好的滤光膜。测试表明:在800～1000 nm波段平均透过率大于99%,在380～780 nm波段平均透过率小于3%,在1064～1270 nm波段平均透过率小于2%,该滤光膜可以满足车载主动式红外夜视系统环境使用要求。     

新型微光探测器激光防护材料的研究

系统分析了微光夜视器的结构及其原理，并结合当前器件存在的激光致盲威胁，提出了增强系统安全的新措施。同时，系统地介绍了防激光滤光材料一些重要的性能参数以及滤光材料的组成、制备加工工艺。研究结果表明，新型的防激光材料能够有效地防护800nm，900nm以及10613nm等三个波长的激光，并且可见光透过率大于85％。     

化学水浴法制备ZnS薄膜光学性能

利用薄膜分析系统测量不同沉积时间制备的ZnS薄膜透射谱,通过分析薄膜透射谱,来确定ZnS薄膜光学常数和禁带宽度.实验结果表明,在线性生长阶段,薄膜的沉积速率大约为1 nm/min,具有很好的线性关系,沉积0.5 h的ZnS薄膜在可见光范围内光透过率为82%左右.     

吸收型近红外滤光薄膜的制备与性能

以聚甲基丙烯酸甲酯(PMMA)为基体,近红外吸收染料NIR756和NIR858为添加剂,采用熔融混合、分散成型的方法制备了近红外吸收滤光薄膜。热失重分析(TG)表明,两种染料都具有较好的热稳定性。透射光谱显示,试样薄膜具有较好的近红外吸收性能,在660nm~930nm波段平均光透过率低于0.2%;同时具有较高的可见光透过率,在400nm~630nm波段平均光透过率高于20%。薄膜具有较好的耐热老化性能。近红外吸收染料在基材中的分散不均匀,有颗粒存在。     

ICP光谱法测定铂饰品中金、铝、铬的谱线选择研究

采用ICP差减法测试铂饰品的过程中,由于基体或杂质元素的部分谱线存在相互干扰,因此会对测试结果产生一定影响。通过测试发现金、铝和铬元素的部分标准推荐谱线不适用于ICP差减法。通过实验证实,金267.595nm,铝396.152nm,铬425.435nm和铬427.481nm不存在铂元素及铁元素的干扰。以上四条谱线元素浓度和光谱强度均呈现良好的线性关系,曲线相关系数大于0.999,测试结果的相对标准偏差(n=11)小于1%,回收率为98.2～100.2%。谱线测试结果准确,灵敏度高,适合作为差减法测定铂饰品含量的分析谱线。     

S掺杂ZnO薄膜光电特性的研究

采用射频磁控溅射法,在玻璃基片上生长了ZnO:S薄膜。XRD测试表明所制薄膜为六角纤锌矿结构,具有明显的(002)衍射峰。室温下的透射光谱测量结果表明,随着S掺入量的增加,ZnO:S合金薄膜的吸收边向长波长方向移动,但在可见光部分有较高的透过率。在此基础上计算了各样品的禁带宽度,结果表明,在S掺入量小于8%的范围内,随着S掺入量的增加,禁带宽度减小。样品紫外光电导特性明显,在波长365nm、功率4000μW/cm2紫外光源照射下,紫外光与可见光所对应光电流响应之比可达3。     

氧化锌掺钇透明导电薄膜的制备及光电特性研究

采用射频磁控溅射法,室温下在玻璃衬底上制备出了具有良好附着性、低电阻率和高透过率的新型透明导电薄膜YZO(ZnO掺杂Y2O3简称YZO)。在薄膜厚度为600nm的情况下,研究了薄膜电学特性随溅射功率和溅射气压的变化情况。X射线衍射谱表明YZO薄膜是多晶膜,具有ZnO的六角纤锌矿结构,最佳取向为(002)方向。最佳溅射条件下制备的薄膜电阻率为8.71×10-4Ω.cm,在可见光范围内平均透过率达到92.3%,禁带宽度为3.57eV。     

PET基近红外吸收滤光片的制备及其夜视兼容性能

采用溶剂混合法将近红外吸收染料分散在丙烯酸树脂中制成近红外吸收涂料,再将涂料与PET薄膜复合制备了一种应用于夜视兼容照明的柔性近红外吸收滤光片。研究了两种近红外吸收染料ND736和ND865的光谱吸收特性,确定了两种近红外吸收染料的配比,并对滤光片的色度进行了调整。结果显示,滤光片在665~930nm波段的光线平均透过率为0.14%,在400~625nm波段的光线平均透过率为22.35%,白光LED光经滤光片滤光后的色度为(u′=0.165,v′=0.508)。经环境实验后,滤光片的光学性能未发生明显变化,具有良好的实际应用性能。     

电感耦合等离子体发射光谱法测定切削液中铁、铜、铝元素含量

本文介绍了利用电感耦合等离子体发射光谱法(ICP-OES)同时快速测定切削液中铁、铜、铝元素的方法。确定各元素分析谱线为:铁238.204nm、铜327.393nm、铝396.151nm。检出限分别为铁0.010μg/mL,铜0.003μg/mL,铝0.006μg/mL,相对标准偏差(RSD,n=11)均小于5%,加标回收率在94～105.5%之间。此方法测定结果快速准确可靠,可用于企业实际生产检测需要。     

1064 nm负滤光片的设计与制备北大核心CSCD

针对当前可见-近红外光电探测器的激光防护要求,研究了1064 nm负滤光片的设计和制备。基于等效折射率理论,综合考虑光谱和场强分布优化,设计了由SiO2/Y_(2)O_(3)/H4组合的规整膜系和SiO2/H4组合的非规整膜系负滤光片;采用离子束辅助热蒸发沉积方式对负滤光片进行了制备,并测试了其光学和抗激光损伤性能。结果表明:在膜系结构G|(0.5LH0.5L)s|A两侧匹配减反膜可以有效减小通带波纹,调整膜系最外层厚度可以同时改善膜系的光谱特性和电场强度分布。镀制的规整膜系负滤光片在400~900 nm和1200~2000 nm波段平均透过率分别为89.98%和93.21%,1064 nm透过率为1.29%,激光损伤阈值为6.0 J/cm^(2);非规整膜系负滤光片在650~900 nm和1200~2000 nm波段平均透过率分别为93.70%和94.99%,1064 nm透过率为1.60%,激光损伤阈值为6.8 J/cm^(2)。     

梯度折射率宽带减反射光伏玻璃研究

采用二次腐蚀法制备了梯度折射率减反射光伏玻璃。SEM分析表明,多孔减反射层的微结构尺度在20～30nm左右,膜层厚度为100～300nm。通过计算模拟,确定了膜层折射率分布形式为Gaussian-like型。制备的梯度折射率减反射光伏玻璃透过率>96%的带宽超过了1200nm;在390～1022nm波段的透过率>99%;在350～1084nm的双面反射率<1%,其中624～922nm的双面反射率低于0.2%。     

Design of a lithium niobate Fabry-Perot étalon-based spectrometer

The design of a tunable Fabry-Perot étalon-based filter that has a passband of 0.01 nm and a free spectral band larger than 50 nm when operated in the center of the visible spectrum is described. The filter consists of two Y-cut lithium niobate étalons having thicknesses in a vernier ratio. The polarization state of light passing through the tandem étalons is rotated 90 degrees before again being transmitted through the étalon pair. If the components are arranged in a symmetrical manner, the filter will operate with unpolarized incident light. Each étalon in double pass will have a greater transmittance than two individual étalons of the same average optical thicknesses, since variations in the physical thickness due to fabrication errors are correlated.     

Visible reflectance hyperspectral imaging: characterization of a noninvasive,in vivo system for determining tissue perfusion

We characterize a visible reflectance hyperspectral imaging system for noninvasive, in vivo, quantitative analysis of human tissue in a clinical environment. The subject area is illuminated with a quartz-tungsten-halogen light source, and the reflected light is spectrally discriminated by a liquid crystal tunable filter (LCTF) and imaged onto a silicon charge-coupled device detector. The LCTF is continuously tunable within its useful visible spectral range (525-725 nm) with an average spectral full width at half-height bandwidth of 0.38 nm and an average transmittance of 10.0%. A standard resolution target placed 5.5 ft from the system results in a field of view with a 17-cm diameter and an optimal spatial resolution of 0.45 mm. The measured reflectance spectra are quantified in terms of apparent absorbance and formatted as a hyperspectral image cube. As a clinical example, we examine a model of vascular dysfunction involving both ischemia and reactive hyperemia during tissue reperfusion. In this model, spectral images, based upon oxyhemoglobin and deoxyhemoblobin signals in the 525-645-nm region, are deconvoluted using a multivariate least-squares regression analysis to visualize the spatial distribution of the percentages of oxyhemoglobin and deoxyhemoglobin in specific skin tissue areas.     

中波红外短波通滤光片的设计与镀制技术研究

研究了中波红外宽光谱短波通滤光片优化设计和镀制,论述了设计该种滤光片的原则和方法。根据等效折射率理论,以周期性对称膜系为基础,使用部分膜层优化方法,设计了中波红外宽光谱短波通滤光片,在2 300～4 700 nm透射波段范围上的平均透射率设计值大于90%,在5 000～6 300 nm截止波段范围上的平均透射率小于1.00%。采用"会聚光红外光学系统"和等离子体辅助沉积工艺实验制备了滤光片。实验表明,在透射波段范围上的平均透射率约为83%,截止波段的平均透射率约为0.45%。结果表明,部分膜层优化方法设计的膜系,膜层结构简单,有利于膜层厚度的监控。     

Accurate and precise wavelength calibration for wide bandwidth array spectrometers

Calibrating the wavelength scale of an array spectrometer typically involves measurements of lines at well-known wavelengths from a calibration lamp such as a mercury-argon source. This process is relatively straightforward when the lines are well separated, relative to the bandwidth of the spectrometer. When the spectrometer's bandwidth is large, compared with the distance between calibration wavelengths, it becomes increasingly difficult to accurately locate lines in the calibration spectrum. Even calibrations for instruments with a modest bandwidth of 12 nm can be difficult. Here we present results from a simple approach to improve the accuracy of wavelength calibration for an instrument with a large bandwidth (12 nm, center-to-center pixel spacing 3.3 nm). A monochromator has been used to filter the source so that each calibration line can be measured separately. For ten spectrometers, we were able to achieve accuracy better than 0.12 nm, or 0.09 nm on average; this is less than 3% of the pixel spacing. We anticipate this approach will be useful for improving the accuracy of measurements on array spectrometers and particularly in transferring multivariate calibrations between instruments.     

Deposition of a conductive near-infrared cutoff filter by radio-frequency magnetron sputtering

We have designed a conductive near-infrared (NIR) cutoff filter for display application, i.e., a modified low-emissivity filter based on the three periods of the basic design of [TiO2[Ti]Ag] TiO2] upon a glass substrate and investigated the optical, structural, chemical, and electrical properties of the conductive NIR cutoff filter prepared by a radio frequency magnetron sputtering system. The results show that the average transmittance is 61.1% in the visible, that the transmittance in the NIR is less than 6.6%, and that the sheet resistance and emissivity are 0.9 ohms/square (where square stands for a square film) and 0.012, respectively, suggesting that the conductive NIR cutoff filter can be employed as a shield against the hazard of electromagnetic waves as well as to cut off the NIR.     

溶胶-凝胶旋涂法制备电致变色智能窗用钛酸锂薄膜

从可见光到近红外波段透过率可调制的电致变色材料, 对于智能窗及其热管理方面的应用来说极具吸引力。钛酸锂是一种有潜力的电致变色阴极材料, 但对其在智能窗领域的应用前景还缺乏相关的数据支持。本工作采用溶胶-凝胶旋涂法制备透过率高、结晶性好的钛酸锂(Li₄Ti₅O₁₂)薄膜, 通过联用电化学工作站和紫外-可见分光光度计原位表征了其电致变色性能。实验发现所有Li₄Ti₅O₁₂薄膜对扫描速率等测试条件十分敏感, 且有优异的双波段调制性能。此外, Li₄Ti₅O₁₂薄膜厚度对材料的初始态透过率、调制幅度、响应时间、电压窗口和循环耐久性均有显著影响。其中450 nm厚的Li₄Ti₅O₁₂着色/褪色响应时间分别为19.1和8.9 s, 透过率调制在可见光区(550 nm处)为45%, 经过20000 s连续循环, 性能未发生明显衰退。Li₄Ti₅O₁₂薄膜在近红外波段(1000 nm处)的透过率调制高达80%, 表现出优秀的节能潜力。本研究成功组装了由灰色至蓝色、循环性能良好的全固态无机电致变色器件: Glass/FTO/Li₄Ti₅O₁₂/LiNbO₃/NiO_x/ITO, 证明钛酸锂作为电致变色智能窗材料有潜力走向普及应用。     

Synthesis and characterization of Cu(II) containing PMMA co-polymer for optical applications

Homogenous, transparent, greenish blue Cu(II) containing PMMA co-polymer disks were prepared through the radical polymerization of the Cu(II) methacrylate, MMA and HMA using AIBN as an initiator. The dependence of the absorbance and transmittance spectra with the Cu(II) methacrylate concentration was investigated in the visible range (420–750 nm). From the transmittance measurements the refractive index and extinction coefficient spectral dependence were calculated by application of an inversion approach. To further characterize this co-polymer a thermogram was performed. The overall behavior of this material suggests its possible use as a standard solution for Spectroscopy Equipment Calibration and as a selective optical filter.     

膜层厚度对Ag/TiO膜透光隔热性能的影响

采用磁控溅射工艺制备了玻璃基Ag/TiO_2膜,并研究了膜层厚度对其透光隔热性能的影响。结果表明:当Ag膜厚度由6.7 nm增加到9.5 nm时,红外光的平均透过率由42.06%减小到7.70%,隔热温差由1.9℃增大到5.7℃,而可见光的平均透过率则呈现出先增加后减少的变化趋势,当Ag膜厚度为7.7 nm时,复合膜的可见光平均透过率达最大值,为70.85%;当Ti O_2膜厚度由4.1 nm增加到16.7 nm时,红外光的平均透过率由34.12%增大到38.28%,而可见光的平均透过率与隔热温差均呈现出先增大后减少的变化趋势,当Ti O_2膜厚度为10.4 nm时,复合膜的可见光平均透过率达最大值,为70.85%,而厚度为13.6 nm时,膜的隔热温差达最大值,为5.2℃。     

Identical-dual-bandpass sampled fiber Bragg grating and its application to ultranarrow filters

We have theoretically proposed and experimentally demonstrated a new kind of ultranarrow identical-dual-bandpass sampled fiber Bragg gratings (SFBGs) with a pi phase shift technique. The spacing of two bandpasses of the proposed grating can be flexibly adjusted by changing the sampled period, and any desired spacing can be achieved in principle. An experimental example shows that the transmission peaks of two narrow transmission-band are near 1549.1 and 1550.1 nm. Based on the proposed SFBG, an ultranarrow identical-dual-channel filter is designed. Two channels of the proposed filter have an equal bandwidth, an even strength, and the same group delay. The bandwidth of each channel of our filter is as small as 1 pm and up to 10(-3) pm (corresponding to approximately 0.1 MHz), which is less than the bandwidth of the conventional SFBG filters by a factor of 10(2)-10(4). The proposed grating and filter can find potential applications with slow light and dual-wavelength single-longitudinal-mode fiber lasers.