压缩光的相位共轭

本文讨论了后向简并四波混频过程中,当入射探测模处于压缩态时,相位共轭模、透射的探测模以及两者的组合模的量子统计性质。结论是,相位共轭模总是非压缩的、超泊松分布的,说明这种相位共轭是一种本质上有噪音的过程;但透射的探测模在一定条件下可保持是压缩的,或亚泊松分布的,     

非线性微腔的光学双稳态

基于F-P腔理论,通过引入有效折射率概念,研究了非线性微腔的光学双稳态,给出了相应的解析表达式。理论曲线与其它文献的数值模拟结果相吻合。研究表明,系统要产生双稳态现象,必须对入射光预置一定的偏移量。若介质是聚焦型Kerr介质,入射光波必须红移;反之则蓝移。临界的偏移量是腔共振模线宽的0.866倍。     

金属膜衬底上亚波长介质光栅结构的特性及传感应用

提出亚波长介质光栅-金属膜-石英玻璃衬底结构,根据等效介质理论该结构可等效为由金属-光栅-包覆层构成的单面金属包覆波导,在入射波长和入射角满足一定条件时,发生导模共振(GMR)从而产生光波全吸收现象。根据严格耦合波分析(RCWA)理论进行数值分析发现,等效波导中的TM1 GMR峰尖锐,并且对光栅包覆层的折射率变化非常敏感,角度灵敏度为127.87°/RIU(RIU为折射率单位),波长灵敏度为409.35 nm/RIU,在很大的折射率范围内线性度良好。与全介质GMR传感器和光栅型表面等离子体共振(SPR)传感器相比,该结构通过GMR实现较高灵敏度的同时,其较窄的共振峰使得检测精度更高。     

非线性介质表面任意阶谐波的反射和透射

本文详细分析了线性介质与非线性介质界面任意阶谐波的反射和折射定律；导出了反射波和透射波的精确表达式，对泵浦波正入射（垂直于界面入射）时，满足相位匹配的场进行了深入的讨论。     

光子晶体Bragg镜的相移特性及腔模研究

研究了光子晶体Bragg镜的反射相移及透射相移，发现随着入射光频率的增大，相位均在增大。在中心频率附近反射相移和透射相移都与频率成线性关系。利用泰勒展开式的一级近似，得到了中心频率附近反射相移和透射相移的一级近似解析解，它们能很好地描述相移的变化规律。利用相移特性研究了Bragg微腔的共振模随微腔厚度的频率变化特性，同时亦给出了中心频率附近共振模频率的一级近似解析解。     

BaTiO_3:Ce自抽运相位共轭产生机理随抽运光入射参数的变化

实验发现当抽运光波长为514．5nm时,随入射到光折变晶体的抽运光参数（光斑尺寸,入射位置和入射角度）改变,BaTiO3∶Ce自抽运相位共轭的形成机制在双作用区四波混频（FWM－TIR）,四波混频-受激背向散射（FWM-SPB）和FWM-TIR＋FWM-SPB之间转变。     

相位共轭光腔的基本物理性质

用一面由四波混频非线性相互作用产生的相位共轭镜(PCM)和另一面真镜(RM)组成的相位共轭光腔(PCR),将会得到十分优良的性质。 为了描写PCM的运转特性,Yariv等和Siegman等定义了该元件光线变换矩阵的第一形式(M_(PCMI));并已由此得出PCR若干有用的性质。但,M_(PCMI)并没有包含相位共轭运算,ABCD定律不再适用,需要人为地加置共轭,给腔模的分析带来很大的困难。 本文定义了PCM变换矩阵的第二形式(M_(PCMH))。所有的变换(包括共轭运算)均包含在M_(PCMH)的矩阵元中,普通的ABCD定律仍然适用,从而非常简洁地导出了PCR的基模。进一步运用M_(PCMH),得到了基模的微扰稳定性、高价模和非简并模。     

’87联合激光学术报告会(论文摘要)

背向受激布里渊散射(BSRS)相位复共轭波传输特性的研究刘邦群招倩儿李道华刘祖荫(武汉大学)对受激布里渊散射产生的相位复共轭波传输特性进行了研究。实验采用染料Q开关红宝石激光脉冲,分别泵浦光导纤维和CS2CCl4等液体管。我们认为,入射激光通过无规相位板进入散射介质的那部分光建立起相应的散斑场,而背向散射波的各种可能模式中,同入射散斑场共轭的模式,其增益大于其它模式,经过适当长度的相互作用距离后,散射介质内的共轭模式超过其它模式而成为BSRS波输出,因而能较好地复原图象。     

弱高斯光阑近似和相位共轭腔

本文证明了在弱高斯光阑近似下,相位共轭腔中不存在确定模,只有当非弱高斯光阑处于腔中或相位共轭镜之前,相位共轭腔才具有确定的模。     

利用单负材料设计全向滤波器

基于法布里-珀罗腔理论,研究了由2块相同单负材料作为反射镜构成微腔结构的共振特性。若反射镜是负ε材料,在一定条件下可实现TM腔模的全向透射;若是负μ材料,则可实现TE腔模的全向透射。随着入射角的增大,全向透射谱变窄,品质因子提高。腔中介质折射率的提高,可有效缩短TM全向透射微腔结构的尺寸,但对TE全向透射微腔结构尺寸的调制就稍弱。单负材料损耗的存在,不会破坏两种微腔结构的全向共振特性,但随着入射角的增大腔模的透射率有所降低。通过优化处理给出了这两种微腔结构能实现全向透射时所需满足的各种条件,为全向滤波器的设计提供理论指导。     

Enhancement effect of phase-conjugate waves of third order nonlinear medium in the Bragg microcavity

It is desiredthat the photon mode could be controlledby using photonic crystal ,such as threshold-less laserdevices[1].The key problemin fabricating photonic de-vices is howtointroduce a defect state[2]into a photoniccrystal ,nevertheless it is difficult …     

一维光子晶体非线性微腔的缺陷模和双稳态

为了了解一维光子晶体布喇格非线性微腔产生的缺陷模和双稳态特性,采用数值模拟和理论分析相结合的方法,研究了缺陷层厚度变化和布喇格镜准周期性对缺陷模和双稳态的影响。研究结果表明,缺陷层厚度增大和折射率递增时,均可使缺陷模向低频方向移动,即布喇格腔共振模红移,因此,只要较小的入射光强就可使腔共振模红移到入射光模而产生阈值较低的双稳态,数值计算与理论分析是一致的。这对光子晶体微腔的设计有一定的意义。     

电磁波在光栅表面上反射和衍射的理论研究

本文从严格的场匹配方法出发,对电磁波在矩形截面光栅上的反射和衍射进行了理论研究。对这种光栅作为频率扫描天线的计算显示出,不论满足或不满足布喇格条件,在较宽的角度范围内入射,经调节槽宽和槽深都可获得理想的耀射。对于不满足布喇格条件,在两个互易角中较大的一个入射时,-1次衍射波有较高的效率和较宽的频带。而对这种光栅作为奥罗管中反射镜的特性的理论计算指出,它具有极宽的频带。同时本文还给出了不同频率平面波垂直入射时的等效光栅位置,以及电磁波在光栅表面反射时所引起的相位改变。     

Optical Properties of AlGaAs/GaAs Resonant Bragg Structure at the Second Quantum State

Photoluminescence, optical reflectance and electro-reflectance spectroscopies were employed to study an AlGaAs/GaAs multiple-quantum-well based resonant Bragg structure, which was designed to match optical Bragg resonance with the exciton-polariton resonance at the second quantum state in the GaAs quantum wells. The structure with 60 periods of AlGaAs/GaAs quantum wells was grown on a semi-insulating substrate by molecular beam epitaxy. Broad and enhanced optical and electro-reflectance features were observed when the Bragg resonance was tuned to the second quantum state of the GaAs quantum well excitons manifesting an enhancement of the light-matter interaction under double-resonance conditions. By applying an alternating electric field, we revealed electro-reflectance features related to the x(e2-hh2) and x(e2-hh1) excitons. The excitonic transition x(e2-hh1), which is prohibited at zero electric field, was allowed by a DC bias due to brake of symmetry and increased overlap of the electron and hole wave functions caused by electric field.     

GaAs参量振荡产生太赫兹波的腔相位匹配研究

基于腔相位匹配的方法,研究了GaAs微片状晶体构成的光学微腔光参量振荡产生太赫兹波的条件与参数设计.计算了腔相位匹配下GaAs晶体的最优化腔长,通过调节GaAs晶体的温度研究了太赫兹波的输出情况,模拟了不同波长下最低的能量阈值.结果表明,在完全相位匹配很难实现的情况下,采用腔相位匹配能很容易地实现大范围的太赫兹波调谐输出.结果为小型化光学太赫兹源的实验与理论研究提供了参考.     

An (AlGaAs/GaAs/AlGaAs)<Subscript>60</Subscript> resonant Bragg structure based on the second quantum-confinement level of heavy-hole excitons in quantum wells

Photoluminescence and optical-reflection spectra of a periodic structure consisting of 60 tunneling-isolated GaAs quantum wells separated by AlGaAs barriers are studied. The structure is designed so that, for a certain angle of incidence (∼23°), the Bragg resonance condition is satisfied for light with a photon energy equal to the energy of heavy-hole excitons at the second quantum-confinement level in the wells. It is established experimentally that, under the conditions of double exciton-polariton and Bragg resonance, a superradiant optical mode is formed. Dependences of Bragg and exciton-polariton reflection on the angle of incidence and polarization of light and the temperature are investigated.     

The application of porous Si photonic crystals for metal-resonance enhanced fluorescence

This paper has demonstrated the resonance fluorescence enhancement of R6G when gold nanoparticles (Au NPs) deposited in the porous Si photonic crystal device. Both of microcavity (MC) and distributed Bragg reflector (DBR) with different parameters are investigated for making the photon transmission of photonic crystal device play an optimal role in enhancing fluorescence resonance. While minor changes were observed on the DBR substrates, a significant change in the intensity of enhanced fluorescence varies with the defect modes of MC substrates. Particularly, the strongest enhancement has been presented as the MC defect mode wavelength located at the maximum absorption wavelength of Au NPs. In this case, the fluorescence intensity of R6G on MC device is 2.5 times of that of R6G based on DBR device.     

Optical properties of a total-reflection-type one-dimensionalphotonic crystal

We produced an asymmetric Fabry-Perot microcavity using total reflection, and its optical properties were investigated. The structure is considered to be a total-reflection-type 1-D photonic crystal. An electric-field enhancement of incident light in a defect layer installed inside the photonic crystal was observed by fluorescence emission from dye molecules doped into the defect layer division. We confirmed that the incident light intensity was strengthened by about 63 times in the defect layer