双面金属包覆介质波导模序数的判别方法

在双面金属包覆介质波导中 ,随着介质层厚度的变化 ,会出现TM0 模与TM1 模的分离和简并两种状态 ,从而影响衰减全反射 (ATR)谱中模序数的确认。通过对金属波导的理论分析和实验研究 ,提出了三种模序数确认方法 :本征角计算法、吸收峰全峰半宽比较法和吸收峰峰间距比较法 ,实现了两种状态下对模序数的准确判断     

基于单通道反射型电光调制器实现不同路光同时调制的方法

提出了一种利用单通道反射型聚合物电光调制器同时调制不同路光的方法。衰减全反射结构的电光调制器,其每一个衰减全反射(ATR)峰的位置分别对应于一个导波共振模式。实验系统中利用衰减全反射导膜峰作为调制通道,使其每一路光路的入射角分别对应于不同导波共振模式的工作角,就可以实现利用单通道的电光调制器同时调制不同路光。提出了三种实现两路光同时调制的模式,并给出了三种模式的调制结果。结果表明,作为调制通道的导模阶数越低,调制效率越高。在832 nm光波波长下,采用最低阶导模进行调制时可以获得42.9%的调制效率。     

Catalyst-and additive-free selective sulfonylation/cyclization of 1,6-enynes with arylazo sulfones leading to sulfonylated γ-butyrolactams

A convenient and regioselective sulfonylation/cyclization of 1,6-enynes with arylazo sulfones has been developed to access a series of sulfonylated γ-butyrolactams.The present reaction could be efficiently conducted under catalyst-and additive-free conditions,in which C-S and C-C bonds were selectively constructed in one-pot procedure.     

Ni,Ru掺杂CePO4纳米材料的合成与仿酶性质

通过水热方法合成了具有高比表面积的Ni, Ru掺杂CePO₄纳米粒子(NiRu-CePO₄). 结合纳米粒子的X射线衍射(XRD)、 扫描电子显微镜(SEM)、 透射电子显微镜(TEM)和X射线能谱(EDX)的表征结果发现, NiRu-CePO₄符合六方相磷酸铈, 纳米粒子长轴尺寸约为20 nm, Ni和Ru均匀分布于纳米CePO₄中; 样品的BET表面积高达178.4 m²/g, ζ电势为-18.2 mV. 以3,3',5,5'-四甲基联苯胺(TMB)作为电子供体和显色剂, 通过分光光度法监测652 nm处的吸光度值对产物浓度进行分析, 结果表明, NiRu-CePO₄催化剂在宽泛的pH范围内表现出类过氧化物酶和类氧化酶活性. 对催化后的催化剂进行表征, 发现样品形貌、 元素分散性和表面Ce的价态均未显著变化, 表明NiRu-CePO₄具有较高的稳定性.     

Analysis of planar waveguides with index discontinuity or index slope discontinuity

In this paper, we propose a novel analytic transfer matrix method (ATMM) to the analysis of planar waveguides with index discontinuity or index slope discontinuity, for the cases when the conventional WKB method is no longer valid. We also analyze the physical insight of the approximations in WKB theory, and according to our research, the phase shift at the turning point is not /2, but exactly . Test calculations are done for an index profile with a known solution and the comparison shows that our method gives extremely accurate propagation constant.     

Ultrafine optical-frequency tunable Brillouin fiber laser based on fiber strain

We present an ultrafine tunable single-frequency Brillouin fiber laser in which the fiber Brillouin gain also acts as a high-precision tunable filter. Controlling the strain on the fiber, the Stokes frequency shift may be precisely changed, and thus the lasing frequency can be tuned. Assisted by the frequency pulling effect, this method provides continuous ultrafine tuning ability for ~30% of the free spectral range without mode hopping, and can cover 271 MHz. The experiments showed that the laser achieves tuning step of 60 kHz.     

Construction of the refractive index profiles for few-mode planar optical waveguides

We present a nondestructive technique to predict the refractive index profiles of isotropic planar waveguides, on which a thin gold film is deposited to as the cladding. The negative dielectric constant of the metal results in significant differences of effective indices between TE and TM modes. The two polarized modes and a surface plasmon resonance (SPR) with abundant information of the surface index can be used to construct the refractive index profiles of single-mode and two-mode waveguides at a fixed wavelength.     

分层复合材料光波导的非线性二次增强效应

通过对分层复合材料光波导ＴＭ模等效介电系数的分析，清楚地预言了无限扩展分层复合材料结构中的非线性增强将因光波导的边界作用而引起进一步的加强。     

Second-harmonic properties of dendritic polymers skeleton-constructed with azobenzene moiety used for nonlinear optical materials

A series of dendrons and dendrimers skeleton-constructed with azobenzene moiety were synthesized and doped in a high T_g polycarbonate (PC) as a host for nonlinear optical (NLO) materials. The optimal loading density and poling conditions were investigated using UV-vis spectral and second-harmonic generation (SHG) measurements. The results showed that the dendrons and dendrimers have good solubility in PC host, which increased with the generation increased. Moreover, the SHG measurements indicated that the dendrons possess higher nonlinearity than the dendrimers. The chromophores of lower generation dendrons were easier to orient along the poling electric field and gave a cone shape with the azobenzene branching units, which coherently contributed to the molecular hyperpolarizability and resulted in the higher SHG intensity. The temporal stability of the dendrons with 15% loading density was also investigated, and showed that the decaying in nonlinearity was slower for higher generation dendrons.     

Investigation of the influence of photobleaching process on the thermo-optic coefficient of disperse red 1/poly(methl methacrylate) film

The influence of photobleaching process on the thermo-optic coefficient (dn/dT) of disperse red 1/poly(methl methacrylate) film is investigated by using the attenuated total reflection technique. Experimental results show that the absolute values of the thermo-optic coefficient of fully bleached disperse red 1/poly(methl methacrylate) film are smaller than those of unbleached film. Moreover, the absolute value of anisotropy of the thermo-optic coefficient (dn_TE/dn_TM/dT) also decreases after the disperse red 1/poly(methl methacrylate) film that is fully bleached.