Phase sensitivity with a coherent beam and twin beams via intensity difference detection

We focus on the Mach–Zehnder interferometer(MZI) with the input of a coherent beam and one of the bright entangled twin beams with an external power reference beam employed for measurement. The results show that the phase sensitivity can reach sub-Heisenberg limit and approach quantum Cramer–Rao bound by changing the squeezing parameters and the photon number of the coherent beam, under the phase-matching condition. The absence of the external power reference beam will degrade the performance of...     

Research on the acoustic scattering function and coherence properties from rough seafloor based on finite element model

Acoustic scattering from a rough sea bottom is recognized as a main source of reverberation. In this study, scattering properties from a layered bottom were exploited based on the finite element model. The scattering strength and loss from the layered rough seabed were investigated by ensembling the realizations of rough interface. They were found to be dependent on the thickness of sediment, and interference was significant in the case of thin sediment. Through verification of the finite element model, the scattering loss could be evaluated using the Eckart model with a proper sound speed in the thick sediment. The multiple scattering effect on the sound field was also exploited. It revealed that the effect depended strongly on the bottom type.     

水热法制备Sm2O3微晶薄膜

以氯化钐为起始原料,采用水热法在玻璃基板和Si(100)基板上制备了Sm2O3薄膜,研究了水热反应温度对薄膜晶相、显微结构和光学性能的影响.采用X射线衍射仪(XRD)、原子力显微镜(AFM)和紫外-可见自记式分光光度计等对薄膜的相组成、显微结构和光学性能进行了表征.结果表明:Sm2O3薄膜在玻璃基板和Si(100)基板上均表现出一定的定向生长的特征;Sm2O3薄膜对紫外线有强烈的吸收作用;随着反应温度从170℃ 升高到 185℃,薄膜的结晶性变好,对紫外和可见光的吸收性均增强;薄膜禁带宽度由2.88eV增加到2.95eV.