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911.
The optical characteristics of transparent lead magnesium niobate titanate (PMNT) electro-optic ceramic, including the electro-optic phase modulation, electric hysteresis property and thermo-optic coefficient, are investigated in detail. Based on this novel ceramic, a polarization independent electro-optic switch by using fiber Sagnac interferometer (FSI) structure is realized. An initial π-shift is introduced into the Sagnac loop to eliminate the effect of the polarization orientation of the incident light on the switch performance. Then an electrically controllable PMNT phase retarder is used to switch the optical signal between the reflection and transmission ports. Some theoretical analyses are given and the switch performances are also discussed, including the thermal characteristic and different switching frequency response. 相似文献
912.
A new daughter wavelet definition for reliability-guided phase unwrapping of the optical fringe pattern is introduced. The new daughter wavelet definition is given by normalized mother wavelet with a new factor including a Gaussian function. The modulus of the wavelet transform coefficients, obtained by using daughter wavelet under this new daughter wavelet definition, includes not only modulation information but also local frequency information of the deformed fringe pattern. Therefore, it can be treated as a good parameter which represents the reliability of the reconstructed phase data. Mathematical demonstration of this parameter is given. Both the computer simulation and experiment reveal the validity of the proposed method. 相似文献
913.
We propose two optical schemes for implementing the deterministic single-particle and two-particle quantum dense coding using four-qubit cluster states. In the protocols, the photon is neuter particle, so it has longer decoherence time with the environment than other particles. It is easy to implement single-bit gate using the linear optical elements under certain conditions, so the transformations performed on the photons by Alice can be easily achieved. Here the cluster states can be exactly discriminated using the parity detector, PBS and FS-PBS. In addition, the success probabilities of the dense coding are both equal to 1. 相似文献
914.
Zhenghong He Zhicheng Ye Qingyu Cui Jiliang Zhu Hongyue Gao Yuye Ling Hongqing Cui Jiangang Lu Xiaojun Guo Yikai Su 《Optics Communications》2011,284(16-17):4022-4027
We study one-dimensional photonic crystals made of cholesteric liquid crystals with sandwiched isotropic defect layers. Based on the Berreman Fast 4 × 4 matrix method, the dispersion relation of one-dimensional photonic crystals is calculated and the corresponding reflection chromaticity is obtained. It is found that the color shift could be controlled by adjusting the thickness and refractive index of the isotropic defect layers. Compared with conventional structures, the reflection chromaticity of this structure is insensitive to the incident angle, if the thickness ratio of the cholesteric liquid crystals to that of the isotropic defect layers and the refractive index of periodical isotropic defect layers are properly set. Furthermore, the common forbidden bands for both left and right circular polarizations can be obtained, and we also take the wavelength-dependent refractive indices into consideration and obtain the reflected light chromaticity with the incident angle increasing. The proposed device can be used as a reflective color filter in the display industry. 相似文献
915.
In the t-J model, the electron fractionalization is dictated by the phase string effect. We find that in the underdoped regime, the antiferromagnetic and superconducting phases are dual: in the former, holons are confined while spinons are deconfined, and vice?versa in the latter. These two phases are separated by a novel phase, the so-called Bose-insulating phase, where both holons and spinons are deconfined. A pair of Wilson loops was found to constitute a complete set of order parameters determining this zero-temperature phase diagram. The quantum phase transitions between these phases are suggested to be of non-Landau-Ginzburg-Wilson type. 相似文献
916.
A linearized tensor renormalization group algorithm is developed to calculate the thermodynamic properties of low-dimensional quantum lattice models. This new approach employs the infinite time-evolving block decimation technique, and allows for treating directly the transfer-matrix tensor network that makes it more scalable. To illustrate the performance, the thermodynamic quantities of the quantum XY spin chain as well as the Heisenberg antiferromagnet on a honeycomb lattice are calculated by the linearized tensor renormalization group method, showing the pronounced precision and high efficiency. 相似文献
917.
918.
介绍了可调谐二极管激光吸收光谱(TDLAS)波长调制技术的测温原理。通过选择水在1 397.75 nm和1 397.87 nm处两条邻近的吸收线,运用多功能数据采集卡对二极管激光器进行控制和信号采集,实现了TDLAS波长调制技术对标定燃烧炉甲烷/空气预混火焰温度的实时在线测量,测量重复频率为250 Hz。分析了温度测量数据抖动的原因,结果表明燃烧过程中火焰本身温度的抖动是测量结果波动的主要原因,测量系统的A类标准不确定度小于53 K。 相似文献
919.
设计了采用532 nm 种子注入稳频钇铝石榴石(YAG)激光器作为辐射源的基于四通道法布里-珀罗标准具的瑞利和米散射测风激光雷达系统。介绍了激光雷达的多普勒测量基本原理;给出了雷达系统的主要参数,重点对基于分子后向散射信号的外侧双通道标准具的带宽、自由谱间距、峰值间距等指标进行了详细设计与分析,确定了内侧双通道标准具参数;对全系统速度灵敏度、信噪比与探测距离的关系进行了理论模拟。结果表明,可以实现从边界层至对流层高低空一体化探测。 相似文献
920.