一种半环形表面等离子体光波导滤波器的传输特性研究

本文设计并提出一种基于金属-介质-金属结构的带有半环形共振腔的表面等离子体光波导滤波器,利用数值模拟的方法研究了其传输特性。结果表明,在该结构传输谱曲线中形成的滤波阻带位置可以通过改变半环形共振腔的半径来调整。另外由于结构固有的特性,在传输谱曲线上还可以观察到类似等离子体感应透明的传输特性,而且这一特性可以通过改变半环形共振腔与直波导之间的耦合间距和采用面对面放置的双半环结构进行调节。本文所设计的结构可以动态控制光的传输,并可以应用于紧凑型纳米光学器件集成领域。     

Large third-order nonlinear optical properties of C70 fullerene in the infrared regime

The nonlinear third-order optical susceptibility of C₇₀ in a toluene solution is measured for the first time by the method of degenerate four-wave mixing using 10 ns laser pulses at 1.06 m. The third-order susceptibility X _in ⁽³⁾ is 5.6×10^–12 esu for a C₇₀ toluene solution at a concentration of 0.476 g/l. The correspondent magnitude of the hyperpolarizability ₁₁₁₁ of the C₇₀ molecule is 1.2×10^–30 esu which is in a good agreement with the prediction given by the model of a free electron in a spherical box.     

Bulk viscosity for interacting strange quark matter and r-mode instability windows for strange stars

We investigate the bulk viscosity of strange quark matter in the framework of the equivparticle model,where analytical formulae are obtained for certain temperature ranges,which can be readily applied to those with various quark mass scalings.In the case of adopting a quark mass scaling with both linear confinement and perturbative interactions,the obtained bulk viscosity increases by 1-2 orders of magnitude compared with those in bag model scenarios.Such an enhancement is mainly due to the large quark equivalent masses adopted in the equivparticle model,which are essentially attributed to the strong interquark interactions and are related to the dynamical chiral symmetry breaki ng.Due to the high bulk viscosity,the predicted damping time of oscillatio ns for a can on ical 1.4 M⊙ strange star is less than one millisecond,which is shorter than previous findings.Consequently,the obtained r-mode instability window for the canonical strange stars well accommodates the observational frequencies and temperatures for pulsars in low-mass X-ray binaries(LMXBs).     

高比探测率和高速石墨烯/n-GaAs复合结构的光电探测器

混合结构的石墨烯/半导体光电晶体管因其超高的响应度而备受关注.然而,该类光电晶体管通过源-漏电极测试得到的比探测率(D．)容易受到1/f噪声的限制.本文制备了混合结构的石墨烯/GaAs光电探测器,通过源-栅电极测得D*大约为1.82X1011 Jones,与通过源-漏电极测量相比,D'提高了约500倍.这可归因于界面上...     

掺杂对二硼化镁超导体上临界磁场的影响

采用二带Ginzburg-Landau(GL)理论模型,考虑到能带有效质量的各向异性,讨论了MgB2超导体的上临界磁场对角度、温度和相干长度的依赖关系.结果表明,替代杂质越多,上临界磁场越强,这与实验结果符合.     

红外视景仿真技术及其研究进展

从红外视景仿真技术意义出发，介绍了其所包含的几个基本部分；从目标辐射建模、背景辐射建模和大气建模三方面，总结了国内外红外视景仿真技术发展历程和状况。其中列举了国外多个典型红外视景仿真软件和几个较完善红外辐射模型，并统计了2000年以来国内高校在红外视景仿真方面的研究情况。统计数据表明，多个发达国家的红外视景仿真技术已逐步趋于成熟和产品化，而国内尚未开发出功能较完善的红外视景仿真系统，只能仿真较简单场景。     

Copyright protection in digital museum based on digital holography and discrete wavelet transform

A new method to protect the copyright of digital museum based on digital holography is proposed. The Fresnel hologram of watermark image is embedded in the object to be protected through discrete wavelet transform （DWT）. After the watermark detection, the copyright information appears in the reconstructed hologram. With the higher redundancy feature in the hologram, the proposed technique can actually survive several kinds of image processing. Experimental results prove that the presented method has good robustness in image protection.     

Study on nitridation processes of β-Ga2O3 single crystal

Nitridated /3-Ga2Os (100) substrate was investigated as the substrate for CaN epitaxial growth.The effects of nitridation temperature and surface roughness of -Ga2O3 wafers on the formation of CaN were studied.     

多元件谐振腔的等价腔

本文使用光学变换矩阵方法，分析了多元件谐振腔的等价腔问题。发展了等价腔的一些概念和方法，推出了在普遍情况下，等价腔各参量与原谐振腔各参量之间的解析关系，并得到了一组不变量；同时，还澄清了一些关于等价腔的错误看法和易混淆之处。