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71.
提出一些折射率比锗还高的中红外材料(第一类)以及中红外反常色散材料(第二类)可以用于无序介质的光子定域化研究.基于Mie散射理论的研究发现,即使在低浓度散射体近似下,也容易在第一类无序介质中实现光子定域化;同时可在第二类无序介质中实现一定意义下(含一定的吸收)的光子定域化,且频率位于各自的剩余射线带内.研究还发现,基质的折射率效应在这两类无序介质中的作用完全不同.还提出了散射体平均等效散射截面饱和的假设,讨论了因此而导致的问题
关键词:
光子定域化
无序介质
中红外
反常色散 相似文献
72.
研究了密立根油滴实验中影响油滴带电的因素,得出了由于温度的升高而引起实验用油粘滞系数降低,从而使油滴带电几率下降的结论,同时提出了增加油滴带电几率的相应对策。 相似文献
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74.
A kind of high birefringence SF6 soft glass photonic crystal fiber (HBSF6-PCF) is proposed. The properties of birefringence, dispersion, nonlinear coefficient and the transmission characteristics are studied by the multipole method and the adaptive split-step Fourier method. The numerical results show that the birefringence and the nonlinear coefficient reach the orders of 10^-2 and 10^-1, respectively. In addition, the HBSF6-PCFs can generate very smooth supercontinuum spectra when illuminated with femtosecond pulsed light of 1064 nm. It is found that up to 800nm spectral width (evaluated at -5dB from the peak) is achieved. Therefore, the advantage of the HBSF6-PCFs is such that a high birefringence, a high nonlinearity and a smooth supercontinuum are perfectly combined in them. 相似文献
75.
设计了一种高双折射高非线性纳米结构光子晶体光纤,利用电磁场散射的多极理论研究了这种光纤的双折射、基模模场、色散以及非线性特性.数值研究发现,加大纤芯及包层空气孔的非对称程度,可使双折射变大,其双折射最大值可达1.918×10-2.通过调节孔节距大小,可将双折射最大值调至所需波长处,孔节距为400nm的纳米光子晶体光纤在800nm波长处非线性系数高达0.2m-1.W-1,同时在750—1000nm的波段有较大的双折射值,高双折射和高非线性在纳米结构光子晶体光纤中实现了完美的结合.对新型纳米光子器件的研制和集成光学的发展具有重要意义. 相似文献
76.
本文设计了两种具有微结构纤芯的光子晶体光纤(PCFs)——矩形芯和椭圆芯PCFs,利用电磁场散射的多极理论研究了这两种光纤的基本特性.发现在光纤包层气孔不变的情况下,仅通过调节纤芯气孔的大小就可以灵活地调节光纤的双折射、色散和非线性特性.随着纤芯气孔半径r1的增大,两种纤芯结构的PCFs表现出如下特点:双折射度增大且最大双折射度对应的波长发生红移,零色散波长由一个增加到三个,短波段非线性系数增大而长波段非线性系数减小.r1=0.4 μm的椭圆芯PCFs的三个零色
关键词:
微结构纤芯光子晶体光纤
双折射
色散
非线性 相似文献
77.
Generation of a mid-infrared broadband polarized supercontinuum in As2Se3 photonic crystal fibers 下载免费PDF全文
A simplified structure of birefringent chalcogenide As 2 Se 3 photonic crystal fiber(PCF) is designed.Properties of birefringence,polarization extinction ratio,chromatic dispersion,nonlinear coefficient,and transmission are studied by using the multipole method,the finite-difference beam propagation method,and the adaptive split-step Fourier method.Considering that the zero dispersion wavelength of our proposed fiber is about 4 μm,we have analysed the mechanism of spectral broadening in PCFs with different pitches in detail,with femtosecond pulses at a wavelength of 4 μm as the pump pulses.Especially,mid-infrared broadband polarized supercontinuums are obtained in a 3-cm PCF with an optimal pitch of 2 μm.Their spectral width at 20 dB reaches up to 12 μm.In the birefringent PCF,we find that the supercontinuum generation changes with the pump alignment angle.Research results show that no coupling between eigenpolarization modes are observed at the maximum average power(i.e.,37 mW),which indicates that the polarization state is well maintained. 相似文献
78.
高次谐波的产生(HHG)是一种获取高频相干光的重要技术。其产生机理为:原子(离子)的外层电子在强激光的作用下产生电离,电离后的电子在激光场的作用下运动,在一定条件下,电子可以回到母离子所在的位置,与离子复合并发出一个高能量的光子,其能量等于电子返回时的动能加上电离能。为了得到很高的光子能量,必须采用高强度的驱动激光。如果激光强度接近10^17W/cm^2或更高时,由磁场产生的洛仑子力将阻止电子回到母离子,因而大大降低高次谐波的产生效率。 相似文献
79.
We report the results of our investigation on the loss property of a birefringent photonic crystal fibre (PCF) based on a particular periodic arrangement of air-holes and pure silica. The structure of the birefringent PCF, whose air-hole diameter in one ring is always larger than the next inner ring, presents an obviously low confinement loss than the one whose air-hole (except those on the horizontal line) diameter is constant. It is shown from numerical results that a four-ring PCF with birefringenee B=5×10^-4 and fast axis confinement loss of 4.5×10^-3 dB/km at wavelength of 1.55μm can be designed. 相似文献
80.