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随着红外目标探测和精确制导技术的广泛应用,传统军事目标面临严峻的生存压力。为此,各主要军事强国采取多种措施,竞相发展目标红外辐射特性控制技术,以降低被红外探测系统捕获的概率,达到红外隐身目的。光子晶体是一种人工超颖材料,可以根据需要,通过灵活地设计其结构,改变光子在其中的传输特性。文中运用一维光子晶体带隙理论,设计了一种控制目标红外辐射特性的结构,详细给出了设计方法。计算结果表明对3~5μm和8~12μm两个红外大气传输窗口,该结构对红外辐射的抑制最高可分别达到29和21dB,具有很好的红外辐射特性控制性能。本文所述方法除为飞行器提供红外隐身设计参考外,还可用于攻防对抗仿真中红外隐身目标特性的模拟。 相似文献
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本文主要阐述了近几年来空间光调制器的研究和应用情况,涉及到它的材料、方法和结构原理等,并围绕我们自己研制的几种典型的器件实例加以说明。 相似文献
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设计了一种新型一维光子晶体慢光波导结构。在常规波导一侧进行了特殊的设计,使波导具有周期性结构,从而具有特殊的色散关系,获得慢光效应。基于麦克斯韦方程利用平面波展开法对光子晶体慢光波导的色散关系进行了分析,获得了波导模以及相应的慢光频率。并利用时域有限差分法(FDTD)对脉冲在波导的传播进行了时域上的模拟,对慢光效应进行验证。 相似文献
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A one-dimensional (1-D) equivalent circuit model for an optically addressed, photodiode-based spatial light modulator (SLM) is presented. The model is first verified for a liquid crystal (LC)-based SLM via a 1-D experimental version of the device followed by a detail simulation using SPICE. It was found that the optical performance of the LC-SLM was most sensitive to the liquid crystal thickness, substrate doping concentration, and the photodiode leakage current. This model can be a useful tool for the analysis of the optical performance (such as photosensitivity and image uniformity) of a variety of photodiode-based SLMs as a function of their structural and operating parameters 相似文献
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提出了一种基于光子晶体和纳米线波导的马赫-曾德尔型调制器.该调制器由硅基光子晶体平板波导、纳米线波导和光子晶体多模干涉耦合器(MMI)构成。在光子晶体与纳米线波导连接处采用了锥型结构,用于减少模式失配造成的损耗。利用时域有限差分法(3D-FDTD)进行仿真分析,结果表明,该调制器在工作波长1 550 nm下的插入损耗为0. 3 dB,消光比为15. 1 dB,器件尺寸仅46μm×8μm×0. 22μm,调制带宽可以达到68 GHz,且工作区域覆盖了以1 551 nm为中心波长20 nm的通信波段。该调制器结构紧凑,易于集成,可应用于高速光通信系统。 相似文献
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V. A. Tolmachev L. S. Granitsyna E. N. Vlasova B. Z. Volchek A. V. Nashchekin A. D. Remenyuk E. V. Astrova 《Semiconductors》2002,36(8):932-935
The potentialities of vertical anisotropic etching of (110) silicon for the fabrication of one-dimensional photonic crystal
with a high refractive index contrast have been studied. It is shown that advances toward the near-IR spectral range are limited
by the mechanical strength of thin silicon walls. The device structures obtained consist of 50 trenches, 114 μm deep, with
1.8-μm-thick Si walls (structure period 8 μm). Their reflectance spectra in the wavelength range 2.5–16.5 μm show good agreement
with calculation results, although the main photonic band gap at λ≈28±10 μm remained outside the spectral region of measurements.
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Translated from Fizika i Tekhnika Poluprovodnikov, Vol. 36, No. 8, 2002, pp. 996–1000.
Original Russian Text Copyright ? 2002 by Tolmachev, Granitsyna, Vlasova, Volchek, Nashchekin, Remenyuk, Astrova. 相似文献
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《Circuits and Devices Magazine, IEEE》2003,19(2):25-33
This paper presents the characteristics of photonic crystal microcavity light sources. Microcavities with dimensions on the scale of the wavelength of light are being extensively investigated due to their ability to exhibit enhanced spontaneous emission, directional output, and single-mode operation. Photonic crystals, which are the optical analog of semiconductors in electronic devices, are capable of controlling the properties of light by confining photons in one, two, or three dimensions. The technology to fabricate photonic crystals at the optical-wavelength scale (i.e., feature sizes at the submicron scale) has only very recently been achieved. Single or multiple defects in the photonic crystals act as microcavities with dimensions on the order of the wavelength of light and have emerged as the preferred way to obtain defect-free optical microcavities. The authors have been investigating electrically injected photonic crystal microcavities, and these devices are described in this paper. Electrically injected microcavities offer the advantage of possible integration with current optoelectronic circuits and devices. Also, arrays of such devices can be fabricated when electrically controlled. Electrically injected photonic crystal microcavity light sources may also realize high-efficiency single-mode LEDs. 相似文献
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首先指出实现慢光的两种不同途径--改变材料色散和波导结构色散,并对利用结构色散产生慢光的光子晶体波导的原理、结构和特征作了说明.然后综述了目前光子晶体波导中产生慢光的新型结构和方法:啁啾结构、耦合结构和优化参数方法,并对它们做了比较.最后简要说明了慢光的研究意义和发展前景. 相似文献
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为了提高液晶空间光调制器用于波前校正的精度,测试了美国BNS公司反射式255×256像素纯相位液晶空间光调制器.由于非线性相位响应特性会降低该器件用于波前校正的性能,因此通过反插值法将相位调制曲线的非线性度减小到原来的1/8,建立了0~2π区间内相位与灰度之间的线性关系.以液晶空间光调制器作为渡前校正器,数字相移干涉仪作为波前传感器,对含有高频误差的不规则波面进行了测量和误差校正.畸变波前的峰谷值(PV)由校正前的0.78A减小到校正后的0.27A,均方根(RMS)由校正前的0.13λ减小到校正后的0.02λ.实验结果表明:液晶空间光调制器能够代替传统的变形镜,实现低成本、高分辨、高精度的波前校正. 相似文献