共查询到16条相似文献,搜索用时 421 毫秒
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《中国无线电电子学文摘》2003,(3)
TN204 2003030149紫夕浩苦设备的组成及工作特点/张洁(电子部53所))I航天电子对抗.一2002,(5)一34一36简介第一代概略型和第二代成像型紫外告普设备的组成及工作原理,并将紫外告瞥方式的特点与雷达告带、红夕隋警方式进行了比较.参3(刚)TN204 2003030150液晶电控双折射特性的研究/王宁.李国华.云茂金(曲阜师范大学))I中国激光.一2002,29(12)一1064一1066在考虑液晶吸收效应的前提下,对向列相液晶BL一009作了电控双折射特性的研究,测出了入射光波长为5 60nm时双折射率随电压变化的关系曲线,同时得到了吸收系数随电压变化的关系曲线.图4参… 相似文献
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为了研究液晶的电控双折射效应在光通信中的应用,采用偏光干涉方法,对液晶透射比随电压的变化情况进行了理论分析和实验验证。在室温20℃下利用岛津UV-3101PC分光光度计,通过改变加在液晶盒两端的电压,获得了入射光波长为1300nm和1550nm时液晶透射比随电压的变化关系曲线。结果表明,当在液晶盒两端加上2V的电压时,波长在1550nm附近有一个比较稳定的高透射带;加2.3V的电压时,波长在1300nm附近有一个比较稳定的高透射带。这一结果对光通信中液晶器件的设计是有帮助的。 相似文献
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通信波段液晶电光特性的实验研究 总被引:1,自引:0,他引:1
利用偏光干涉理论,通过对BL-009型向列相液晶透射比的测试,分析了液晶透射比随电场的变化情况,对液晶的电控双折射效应进行了研究。在20℃下,利用岛津UV-3101PC分光光度计,通过改变加在液晶盒两端的电压,测出了入射光波长为1 330 nm和1 550 nm时液晶双折射率随电压变化的关系曲线。实验结果表明:当液晶盒两端加1 V电压时,入射光波长从1 310 nm到1 350 nm有一较稳定的高透射带;加2 V电压时,从1 520 nm到1 580 nm有一比较稳定的高透射带。 相似文献
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液晶电控效应的实验研究 总被引:4,自引:0,他引:4
详细阐述了液晶的电光效应,介绍了利用分光光度计测量液晶透射比的方法。通过改变加在液晶盒上的电压大小及其频率高低,详细测量了液晶的透射比。通过做图分析了液晶的电控双折射效应,得出液晶的透射比随所加电压的大小和频率的高低而变化,以及液晶的阈值电压随频率的增高而减小的规律,这对液晶器件的设计与研究均具有一定的参考价值。 相似文献
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准确的双折射特性测量对于液晶的实际应用具有重要意义。研究了液晶材料的工作原理,以激光回馈效应为基础,搭建了各向异性外腔回馈双折射测量系统,对不同驱动电压下液晶的双折射特性进行测量。测量结果表明,各向异性外腔回馈双折射测量系统测量精度在0.3°之内;通过施加0~24V交流电压,液晶材料双折射率在2.74×10-1~2.39×10-3范围内变化,对应各向异性呈现出460°~5°的大范围位相延迟值。电压范围在0.7~2V时,电压-双折射率关系表现出较好的线性度,通过线性拟合对该范围内电压-双折射率关系进行计算,其线性度优于95.5%。液晶材料可以提供稳定的位相延迟,同一电压值下的位相延迟短期重复性优于0.52°,长期重复性优于4.5°。 相似文献
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基于液晶的电控双折射特性和光子晶体自准直特性,在二维光子晶体引入复合缺陷提出一种可调谐Mach-Zehnder 干涉(MZI)滤波器结构,应用液晶系统的自由能理论,推导了外加电压与液晶有效折射率的关系,并结合MZI 相位调制原理和光子晶体等效折射率理论,得到液晶的电控双折射特性与MZI 滤波器的输出光谱间的数学关系,运用时域有限差分法(FDTD)对滤波器的输出进行仿真模拟,并根据仿真结果对结构进行一级级联的优化设计。结果表明:通过控制外加电压的大小可以改变输出端的透射波长,达到可调谐滤波的效果,并且一级级联后的滤波效果比级联前有很大的改善,滤波的半波带宽从20 nm 减小为7 nm,可调谐范围从15 nm 增大为40 nm,因此可以通过进一步级联的方式使滤波器结构更加的优化,以便运用到光波分复用系统中。 相似文献
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Hsin-Ying Wu Cho-Fan Hsieh Tsung-Ta Tang Ru-Pin Pan Ci-Ling Pan 《Photonics Technology Letters, IEEE》2006,18(14):1488-1490
Tunable phase shift up to 360/spl deg/ at 1 THz is demonstrated using electrically controlled birefringence in a vertically aligned nematic liquid crystal (E7) cell, 1.83 mm in thickness. The driving voltage and corresponding field required for a phase shift of 360/spl deg/ at 1 THz are 100 V and 90.5 V/cm, respectively. 相似文献
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Electrically controlled room temperature terahertz phase shifter with liquid crystal 总被引:1,自引:0,他引:1
Tsong-Ru Tsai Chao-Yuan Chen Ru-Pin Pan Ci-Ling Pan Xi-Cheng Zhang 《Microwave and Wireless Components Letters, IEEE》2004,14(2):77-79
We present the use of electrically controlled birefringence in a nematic liquid crystal cell for phase shifting of electromagnetic waves up to terahertz frequencies. This device was operated at room temperature and a maximum phase shift of 4.07/spl deg/ was demonstrated at 1.07 THz when the interaction length was 38.6 /spl mu/m. The driving voltage and corresponding field were 176.8 V (rms) and 589.3 V/cm, respectively. 相似文献
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基于光强选通成像的液晶透过谱研究 总被引:1,自引:0,他引:1
为了更好地将液晶器件应用于选通成像系统中,从理论上推导出了液晶器件透过率与波长、折射率、电压之间的关系。从双折射率与光强的关系定量分析了扭曲向列相液晶的色散效应。用光栅光谱仪选择380~1100nm波段,以SONY公司LCX023CMT型号的TFT-LCD为样品,测试了液晶器件在不同灰度级和波长下的透射率。研究结果表明:液晶器件在可见光波段色散较小,随着灰度值的增加,色散增大;通过自制的光强局部选通成像系统对同一物体进行了对比拍摄,选通后的照片表明液晶器件的色散对成像质量影响不大;该液晶器件对红外光线有近12%的透过率,证明其可以实现近红外波段的强光局部选通成像。 相似文献
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Vladimir G. CHIGRINOV 《中国光电子学前沿》2010,3(1)
We developed new optical switches based on nematic and ferroelectric liquid crystal (LC) cells for photonics applications. Certain new LC switches based on the effect of total internal reflection in nematic LC and deformed helix ferroelectric effect ferroelectric LC with very fast response time were developed. Fast bistable optical switches of the light polarization based on ferroelectric liquid crystal cells were proposed. The switches are characterized by 100 us switching time and 26 dB crosstalk at the wavelength of 632.8 nm and bistable, i.e., required zero power consumption in the switch state.High frequency hysteretic free electrically controlled 0-2π phase modulation of light has been proposed using a very short helix pitch (less than 400 nm) deformed helix ferroelectric liquid crystal. The electrically controlled 0-2π hysteretic free phase modulation was achieved at the driving voltage frequency up to 4 kHz and the voltage amplitude of 32 V. The application of fast V-shaped deformed helix ferroelectric ferroelectric LC (DHF-FLC) for new active-matrix liquid crystal display (LCD) and optical data processing devices is envisaged.Photoalignment technology can be very useful for the new generation of liquid crystal devices as well as in new photovoltaic, optoelectronic and photonic devices based on highly ordered thin organic layers. We have investigated the LC photoalignment in superthin tubes, which are basic elements of switchable photonic crystal/liquid crystal structures and obtained the order parameter comparable with usual homogeneous nematic LC cells. We studied LC alignment on silicon surfaces with submicrometer-sized straight and curved waveguide profiles. The liquid crystal cladding refractive index was then varied according to the applied voltage, and subsequently the microresonator resonance wavelengths were tuned. Based on our initial measurements, the free spectral range (FSR) wavelength shift within the range of 20 nm was obtained, which is comparable with a thermooptic effect. The new voltagecontrollable Si-based add drop filters are envisaged based on this principle. 相似文献