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半波孔问题严重影响了倍频分束镜在高功率激光系统中的应用。为研究半波孔的产生机理,分别模拟了由高、低折射率膜层厚度失配和膜料色散失配引起的1/4波长对称规整膜系的半波孔。基于等效层理论,在Matlab平台上计算膜系的等效折射率E,绘出其对应的反射率极值包络曲线。通过研究对称膜系的等效折射率、反射率光谱和反射率包络之间的关系,从原理上分析了半波孔的大小、位置和变化趋势等特点。结果表明,膜层的厚度失配使对称膜系的等效折射率在光谱半波处产生截止带。膜层数越多,膜层厚度和膜料色散的失配越严重,则倍频分束镜的半波孔越深。 相似文献
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论述了基于视场补偿型Savart偏光镜的稳态大视场偏振干涉成像光谱仪的分光机理.依据电磁场边值条件,分析了光在视场补偿型Savart偏光镜中各晶体分界面上的透射情况,得出了透射率的理论计算公式.采用计算机模拟,分析了在半波片为不同材料时,透射率随入射波长、视场角及半波片厚度的变化关系.研究表明,视场补偿型Savart偏光镜具有大视场、高通量、高探测灵敏度的显著特点.此研究可为新型干涉成像光谱技术的研究和新型偏振干涉成像光谱仪的设计、研制提供重要的理论指导.
关键词:
偏振干涉成像光谱仪
视场补偿型Savart偏光镜
透射率
电磁场边值条件 相似文献
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三倍频激光束特性传输变换的近似模型 总被引:10,自引:3,他引:7
针对具有振幅和位相扰动的激光束的三次谐波转换,理论上研究了三倍频激光束特性的传输变换,给出了光束质量M2因子、振幅和位相扰动变换的近似解析模型,可为高功率激光驱动器的设计提供理论依据。 相似文献
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闪电场景模拟系统中需要不同强度分布的光轴平行的多路光束,多棱镜分光系统能够实现平行光束增宽和强度分布调制。为获取彼此平行的多路光束,采用五棱镜扫描法完成等间隔分布的四棱镜分光系统的多光束光轴平行度检测,通过CCD采集返回的与特定光轴位置信息有关的光点光强分布,并编制相关的软件计算质心偏差,为分光棱镜的定位装校提供直观准确的反馈信息,装校装置具有简单方便的特点。装校后的四棱镜分光系统在x、y、z 3个方向上的光轴匹配精度分别小于3、4和4.5,4束平行光的光强之比约为8∶4∶2∶1。进一步提高CCD分辨率和增大成像物镜L的焦距后,光轴的匹配精度可以达到秒量级。 相似文献
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用电子束蒸发及光电极值监控技术在石英基底上沉积了三倍频分离膜,将部分样品置空气中于250 ℃温度下进行3 h热退火处理。然后用Lambda900分光光度计测量了样品的光谱性能;用表面热透镜技术测量了样品的弱吸收值;用调Q脉冲激光装置测试了样品分别在355 nm和1 064 nm的抗激光损伤阈值。实验结果发现,样品的实验光谱性能良好,退火前后其光谱性能几乎没有发生温漂,说明薄膜的温度稳定性好;同时弱吸收平均值从退火前的1.07×10-4下降到退火后的6.2×10-5,从而使对基频的抗激光损伤阈值提高,从14.6 J/cm2上升到18.8 J/cm2,但是三倍频阈值在退火后有显著降低,从7.5 J/cm2下降到2.5 J/cm2。 相似文献
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基于一维金属-介质周期结构的偏振分束 总被引:3,自引:1,他引:2
分析了一维金属一介质周期结构的能带特性,根据一定频率范围内TM波(磁场方向与界面平行)在结构中的负折射以及TE波的正常折射,提出了一种偏振分束器件.利用传输矩阵法(TMM)模拟了该结构对入射高斯光束的偏振分束作用,讨论了不同入射角度下的偏振分束能力,并结合实际金属参量,分析了金属层吸收对结构特性的影响.结果表明该结构在55°附近入射时有最好的性能;在吸收作用下结构偏振分束能力有一定的减小,TM波透射比发生了较大变化,TE波效果较好;随着周期数增加,结构透射比下降,但分光能力显著提高;在工作波段上随着波长增大,金属层吸收对器件的影响减弱.该结构能实现宽波段、宽角度、较高透射比的偏振分束. 相似文献
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We demonstrate a high-throughput and high-damage-threshold beam splitter for high-order harmonics in the soft-x-ray region that uses Si and (or) SiC plates set at Brewster's angle with respect to the pump wavelength. The beam splitters are guaranteed to have a damage threshold of at least 0.8 TW/cm2 (average power density, 0.25 W/cm2) and an attenuation rate of 10(-4)-10(-5) for a 30-fs pump pulse. The measured reflection efficiency at the 27th harmonic (29.6 nm) was 0.56 for Si and 0.45 for SiC. These beam splitters are useful not only for high harmonics but also for longitudinally pumped x-ray lasers. 相似文献
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大角度倾斜入射时,光学薄膜表现出强烈的偏振效应。入射光S分量和P分量的反射率和透射率曲线,以及反射或透射引起的两个分量的相位变化都不再相同,彼此有一定的偏振分离。通过对产生偏振效应内在原因的分析,采用一个在近红外波段对于45倾斜入射光的S分量和P分量等效导纳非常接近的膜系结构,结合单纯形法优化算法,设计得到一个1 500~1 600 nm范围内反射率都是50%的近红外消偏振分光膜。结果显示,在45入射时,S分量和P分量的反射率曲线偏振分离小,反射和透射引起的相位变化也控制在很小范围。 相似文献
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An ultra-high precision thin-film polarizing beam splitter (PBS) has been designed and fabricated. Using Needle optimization technology, we design the thin-film polarizing beam splitter that is transparent for P polarization and reflective for S polarization with ultra-high precision at 64.8° angle of incidence and 632.8 ± 10 nm wavelength band. The experiments with the fabricated thin-film PBS demonstrate that both the reflectance of P polarization and transmittance of S polarization at 64.8° angle of incidence and 632.8 nm wavelength point are less than 0.02%, which is ultra-high for reported PBSs. 相似文献
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Yao Zhang 《Optics Communications》2010,283(10):2140-276
A polarization beam splitter with wide bandwidth and simple structure in air-hole-based periodic dielectric waveguides has been proposed and designed. Operation principle of the device is based on different directional coupling properties of beams in TE and TM polarizations in parallel periodic dielectric waveguides. Performances have been evaluated by a finite-difference time-domain simulation. Results show that the polarization beam splitter provides a wide bandwidth of 113 nm with both a high extinction ratio (higher than 21 dB) and a low insertion loss (less than 1.5 dB) for optical communication wavelengths at ∼1.55 μm. Moreover, the performances of the polarization beam splitter are insensitive to longitudinal alignment errors in the coupling region, which is desirable for device fabrication and practical application. 相似文献
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Second harmonic generation in ammonium malate has been investigated in a wavelength region between 492 nm (short wavelength limit of the harmonic beam at 246 nm) and 640 nm. Phase match angle, refractive indices and all coefficients of the nonlinear susceptibility tensor have been measured; several possibilities for phase matching are discussed. 相似文献
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利用3维软件设计了适用于S波段相对论速调管放大器的单重入输入腔,该腔体采用了偏心设计,以便减小耦合孔处的不均匀场对腔间隙场的影响,分析了腔体耦合孔尺寸对腔间隙场均匀性的影响;建立了带输入波导结构的3维输入腔开放腔模型,并应用此模型,采用3维PIC程序模拟了注入微波功率、束直流对输入腔间隙后束流调制的影响。研究结果表明:耦合孔尺寸对腔间隙电场均匀性影响较大,当耦合孔离轴越近时,腔间隙场越不均匀;在结构参数和束参数固定的条件下,基波电流调制深度随着间隙电压的增加而增加,但达到最大基波调制电流的漂移距离几乎不变;在结构参数和注入微波参数固定的条件下,束直流越大,达到最大基波调制电流所需的漂移距离越短。研究结果为腔体的设计和输入腔束流调制实验提供了参考依据。 相似文献
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We propose and analyze a novel multiway high efficiency composite beam splitter based on propagation properties of the light waves in directional coupler and Y-junction. The splitting properties of the beam splitter have been numerically simulated and analyzed using the PWE and FDTD methods. Then in order to obtain equal distribution of power, we place and adjust some additional rods in the output waveguides to optimize the devices. It was shown that a large separating angle, a high beam rate, high flexibility, has been extended to have more light output channels in the beam splitter. 相似文献
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A novel high-power polarization-independent electro-optic switch technology based on a reciprocal structure Sagnac interferometer and a transparent quadratic electro-optic ceramic is proposed and analyzed theoretically and experimentally.The electro-optic ceramic is used as a phase retarder for the clockwise and counter-clockwise polarized light, and their polarization directions are adjusted to their orthogonal positions by using two half-wave plates. The output light then becomes polarization-independent with respect to the polarization direction of the input light. The switch characteristics, including splitter ratios and polarization states, are theoretically analyzed and simulated in detail by the matrix multiplication method.An experimental setup is built to verify the analysis and experimental results. A new component ceramic is used and a nonpolarizing cube beam splitter(NPBS) replaces the beam splitter(BS) to lower the ON/OFF voltage to 305 V and improve the extinction ratio by 2 d B. Finally, the laser-induced damage threshold for the proposed switch is measured and discussed.It is believed that potential applications of this novel polarization-independent electro-optic switch technology will be wide,especially for ultrafast high-power laser systems. 相似文献
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A polarization beam splitter based on a self-collimation Mach-Zehnder interferometer (SMZI) in a hole-type silicon photonic crystal was proposed and numerically demonstrated. Utilizing polarization dependence of the transmission spectra of the SMZI and polarization peak matching (PPM) method, the SMZI can work as a polarization beam splitter (PBS) by selecting appropriate path length difference in the structure. Because of its intrinsic operating principle, the PBS possesses high polarization extinction ratios (PERs). As its dimensions are only several operating wavelengths, the PBS may have practical applications in photonic integrated circuits. 相似文献
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突破传统涡旋光场束缚,发展短波极紫外涡旋光场是实现阿秒脉冲偏振控制的有效途径.本研究利用自制的平场光栅光谱仪和超快时间保持的单色仪,以800 nm,35 fs高斯或具有偏振奇点的涡旋光脉冲驱动诱导氩原子产生高次谐波,分别获得相应的高次谐波光谱以及谐波谱单阶光源的分布.实验结果表明,基于高次谐波产生实现近红外波段的涡旋光束特性转移到极紫外波段,优化后的极紫外涡旋可以实现每秒108光子数输出.同时发现极紫外波段的涡旋场和高斯场高次谐波产生具有相似相位匹配机制.基于高次谐波产生的极紫外波段的偏振涡旋光为探究和操控原子分子量子态的含时演化动力学以及形成阿秒矢量光束提供了重要的方法和技术手段. 相似文献