红外带通滤光片77 K光谱漂移特性实验研究

红外带通滤光片是决定红外探测器组件光谱响应范围的重要元件。滤光片光谱的截止波长在低温下会产生漂移,从而影响组件的光谱响应范围。为探究滤光片在低温下的光谱漂移情况,选取了几种典型的红外带通滤光片,并分别在常温和77 K温度下使用自制的低温光谱测试杜瓦对其进行了光谱测试。结果表明,低温下滤光片的前截止波长均向短波方向漂移。该漂移量的大小主要与工作波段有关。工作波长越长,漂移量越大。中波红外带通滤光片的截止波长在低温下的漂移量小于100 nm。基片材料对截止波长漂移的影响较小。该结论对于红外探测器滤光片的光谱设计具有重要的参考价值。     

氧化锌半导体薄膜的发光光谱特性

用直流反应溅射方法在Ｓｉ（１００）基片上生长出具有六角晶型的ＺｎＯ薄膜．测量了样品的阴极射线发光特性及其与薄膜晶体结构的关系．在所有测量样品中均观察到较强的绿带（５２０ｎｍ）发射,随着薄膜单晶程度的提高,光谱中开始出现蓝带（～４５０ｎｍ）,并在类单晶薄膜中看到了强度大于绿带的近紫外谱带（３９０ｎｍ）;它的强度随着阴极射线电子束流密度增加而迅速增加．根据ＺｎＯ中激子的结合能数据,推测紫带发射来源于ＺｎＯ的激子跃迁．实验结果说明,通过改进薄膜的结晶状况可进一步增强ＺｎＯ薄膜的短波长发光     

3.5～4.0μm低温光谱带通滤光片的设计与研制

新一代气象卫星对红外带通滤光片的光谱控制提出了很高的要求:滤光片在工作温度(92K)下的光谱曲线被严格限定在一个由内、外框组成的区域之内。分别采用Ge和SiO作为高低折射率膜层材料,设计了含有4个谐振腔的带通膜系来提升通带边缘的陡度;对带通膜系中反射膜层的光学厚度进行了优化调整,压缩了通带内的波纹;根据膜层材料的折射率-温度变化特性,设计出了低温条件下符合光谱要求的带通滤光片。采用真空蒸发和光学极值监控的方法,研制出了92K低温下符合内、外框限制要求的带通滤光片,其通带内的峰值透射率达到93.2%,平均透射率达到91%,波纹幅度控制在5.2%以内。     

亚波长光栅与法布里-珀罗滤光片集成的高性能光谱偏振分光器

光谱偏振成像技术是一种新型的光学成像技术,它不仅提高了目标的信息获取量,还降低了背景噪声,可以捕获目标细节,检测伪装目标。本文提出了一种将亚波长光栅与F-P滤光片相结合的光谱偏振测量器件,该器件可以获得超高光谱分辨率和偏振消光比,并且光谱和偏振可以灵活调控。本文设计了一种光谱偏振同时分光器,可同时获得4个光谱通道的斯托克斯参数。仿真结果表明,其光谱分辨率为217,偏振消光比为。实验结果表明,亚波长光栅的偏振消光比大于500,透射率为90%。全介质F-P滤光片的光谱分辨率为30,在长波红外波段的透射率为60%。该设计方法具有通用性,可用于可见光、红外甚至太赫兹等波段。得益于这些优点,器件在微型偏振光谱仪和全斯托克斯偏振检测等领域有很大的应用潜力。     

遗传算法应用于干涉滤光片的设计

为了设计参量更加优良的干涉滤光片,在光子晶体基础上,利用遗传算法设计了窄带滤光片、宽带阻滤光片宽带通滤光片。进行了总结并对需待完善的地方进行了说明。所设计干涉滤光片可以根据给定材料的折射率,计算出此滤光片的最优化透射率。结果表明,如果评价函数对膜系结构的微小变化敏感,用遗传算法对膜系的优化能获得好的结果和较高的效率。     

邻苯二甲酰亚氨基酞菁锌(ZnPcS2P2)的光谱特性

测定和研究光敏剂的光谱特性,可为确定最佳治疗的光源波长提供直接依据,同时也是荧光诊断中选定检测荧光波长的理论依据．本文研究新型光敏剂邻苯二甲酰亚氨基酞菁锌（ZnPcS2P2）的光谱特性,测出ZnPcS2P2在含10%人血清生理盐水的吸收光谱和荧光发射光谱,并与血卟啉衍生物（HpD）进行比较。实验结果表明：在吸收光谱中ZnPcS2P2的最大吸收峰位于670nm,而HpD的最大的吸收峰在405nm处,所以在光动力学治疗中ZnPcS2P2比HpD效果更好。当用波长为632nm的光源激发时,从荧光发射光谱可知,HpD比ZnPcS2P2获得的荧光激发效率高。因此,HpD在光动力学诊断中有更突出的优点。     

可见光和近红外双带通薄膜滤光片的光谱调控

空间对地观测的遥感相机中需要基于干涉薄膜的双光谱通道滤光片,在同一几何点上同时形成可见光（波长500~720 nm）和近红外（波长1 064±1 nm）两个光谱通道。这两个光谱通道的光谱位置和透射强度均需要进行精确控制。选用JGS-1石英玻璃作为滤光片基片,氧化钽（Ta₂O₅）和氧化硅（SiO₂）分别作为高、低折射率薄膜,由双离子束溅射沉积方法将52层和88层介质薄膜分别镀制在基片的两个表面上。500~720 nm波段的平均透过率达到92%,（1 064±1）nm 波段的峰值透过率控制在（26±1）%的范围。     

多光谱带通渐变滤光片透射率特性分析

分析给出了利用厚端非遮挡区的光谱透射率来计算给定区域光谱透射率的一般积分式,并对通带展宽、峰值降低以及相邻区域的通带重叠现象作进一步分析。     

新型紧凑型带通滤波器的设计

文章设计了两个通带位于超宽带低频范围的带通滤波器,用一种T型结构来代替传统带通滤波器中的四分之一波长传输线,这种替代减小了滤波器的尺寸.而且,可以很方便的控制位于滤波器通带两端的传输零点,即合理的调节开路支线的电长度,进而可以方便的控制滤波器的通带范围.为了证明以上新型滤波器的优点,设计了两个开路支线电长度不同的带通滤...     

具有超宽带吸收特性的Ku波段带通滤波器设计

为解决Ku波段带通滤波器带外反射信号干扰系统性能的问题,研究了一种具有超宽带无反射特性的Ku波段吸收式带通滤波器(Absorptive Bandpass Filter,ABPF).该滤波器基于超宽带多级威尔金森(Wilkin-son)功分器/合成器和超宽带 90°移相器,结合传统反射式带通滤波器,利用进入功分器/合成器...     

A wideband stepped-impedance rectangular-ring resonator bandpass filter with multiple notched bands

A configuration of wideband bandpass filter (BPF) with multiple notched bands is presented. Proposed BPF is based on stepped-impedance resonator. By utilising dual stepped-impedance resonators in folded topology a rectangular-ring resonator is formed. Two notched bands in the passband are achieved without using asymmetrical coupled lines. In other words, the filter configuration is capable of producing notched bands. It should be noted that additional information on filter performance and design is presented. Measurement results are presented to approve propounded filter characteristics. The measured passband of the second proposed filter is from 3.68 to 10.2 GHz with insertion loss of –1.76 dB in the first passband at the centre frequency of 4.45 GHz. The measured notched band frequencies are about 5.45 and 7.95 GHz with rejection of –21.77 and –20.82 dB, respectively. The return loss in the passband is better than –11.4 dB.     

基于T 型谐振器的新型可重构滤波器的设计

基于T 型谐振器结构,设计了一款新型小型化可重构滤波器。它可以通过开/ 关射频开关,实现三种滤波器的重新配置。这三种模式分别为带阻滤波器(BSF)、宽阻带带阻滤波器(WB鄄BSF)和双模带通滤波器(DB-BPF)。设计并制造了一款小型可重构滤波器实物(εr =2.65,h =1 mm)。其中,带阻滤波器的阻带中心频率为3.89 GHz,-3 dB相对带宽为90.9% (2.12 - 5.65 GHz);宽带带阻滤波器的阻带中心频率为3.54 GHz,-3 dB 相对带宽为137.85%(1.1～5.98 GHz);双模带通滤波器的两个通带中心频率分别为1.53 GHz 和6.89 GHz,-3 dB 相对带宽分别为17. 6%(1.4～1.67 GHz)和1.16% (6.85～6.93 GHz),两通带之间回波损耗优于15 dB。实物测试结果与仿真结果基本一致。     

Butterworth Window for Power Spectral Density Estimation

The power spectral density of a signal can be estimated most accurately by using a window with a narrow bandwidth and large sidelobe attenuation. Conventional windows generally control these characteristics by only one parameter, so there is a trade-off problem: if the bandwidth is reduced, the sidelobe attenuation is also reduced. To overcome this problem, we propose using a Butterworth window with two control parameters for power spectral density estimation and analyze its characteristics. Simulation results demonstrate that the sidelobe attenuation and the 3 dB bandwidth can be controlled independently. Thus, the trade-off problem between resolution and spectral leakage in the estimated power spectral density can be overcome.     

Compact microstrip stepped impedance wideband bandpass filter

A novel wideband bandpass filter with a very compact size is presented in this article. Using a side-coupled stepped impedance resonator, wideband characteristics with adjustable centre frequency and 3-dB fractional bandwidth can be obtained easily. Finally, a filter sample is designed and fabricated to provide an experimental verification on the proposed topology. Good insertion/return losses, flat group delay, wide bandwidth as well as ultra compact size are achieved as demonstrated in both simulation and experiment, which makes this filter a very promising candidate for applications in future wideband communication system.     

宽光谱声光可调滤光器

由于压电换能器的工作带宽有限,从而限制了声光可调滤光器工作的光谱范围.该文介绍了一种通过在同一个通声面上制作多片厚度不同的换能器的方式来提高声光可调滤光器的工作带宽,进而达到提高光谱范围的方法.采用这种新方法,理论上可制作出全光谱的声光可调滤光器.实验表明,使用两片换能器的声光可调滤光器,其工作带宽接近0.9个倍频程,光谱范围0.45～0.95μm,衍射效率大于70％,光谱分辨率小于7 nm,光孔径(φ)8 mm×8 mm.     

Compact tri‐wideband bandpass filter with multiple transmission zeros

This paper presents a tri‐wideband bandpass filter (TWB‐BPF) with compact size, high band‐to‐band isolation, and multiple transmission zeros (TZs). The proposed TWB‐BPF is based on a multiple‐mode resonator (MMR), which is interpreted by the method of the even‐ and odd‐mode analysis technique. The MMR can excite 11 resonant modes, where the first two modes comprise the first passband, the next four modes form the second passband, and the last five modes are used to generate the third passband. In addition, 10 TZs are yielded to obtain high band‐to‐band isolation and wide stopband suppression characteristics up to 14.95f_c1 (f_c1 is the center frequency of the first passband). To verify the proposed filter, a TWB‐BPF with 3‐dB fractional bandwidths (FBWs) of 37.4%, 43.5%, and 40.4% is designed, fabricated, and measured.     

波导带通滤波器的精确设计和快速优化

介绍了采用三维微波电磁场仿真软件快速提取直接耦合波导带通滤波器耦合窗口参数的方法,并提出了优化最终模型的快速扫描技术.全波仿真及实验结果表明,该方法能满足波导带通滤波器快速精确设计的要求.     

Design of Switchable and Reconfigurable Semi‐lumped Wideband Bandpass Filter

A switchable single‐wideband (SWB)‐to‐dual‐wideband (DWB) bandpass filter (BPF), which is realized by using lumped switches, is presented in this paper. By alternating the operation modes—ON and OFF—in which the ON mode is achieved by placing the capacitors at the switching spots and the OFF mode is achieved by replacing the capacitors with inductors, DWB‐to‐SWB BPF can be achieved on the same device. In addition, by changing the capacitor values, the center frequency (CF) of the lower passband of DWB BPF can be easily tuned from 1.69 GHz to 2.22 GHz, while the higher passband stays almost unchanged. As an example, an SWB‐to‐DWB BPF is designed, fabricated, and measured. This BPF exhibits good performance including wideband, high isolation, compact size, and ability to switch.