一种胶体光子晶体修饰的光纤

设计了一种胶体光子晶体修饰的光纤. 采用恒温快速蒸发法直接在经切割刀处理后的光纤端面生长胶体晶体,再与另一根切割后的光纤在毛细玻璃管中完成对接,制备成胶体光子晶体修饰的光纤. 用扫描电子显微镜和光谱分析仪对样品的形貌、结构以及光学特性进行分析. 实验结果表明,粒径为640 nm、体积分数约为0.5%的SiO₂胶体微球溶液在60 ℃的情况下沉积,大约12 h后可得到质量较高的胶体光子晶体. 在SEM下,观察到端面的胶体晶体为面心立方(fcc)结构. 透射光谱证明,该结构在(111)面上     

采用溶胶凝胶协同自组装方法制备SiO2反蛋白石结构薄膜及其光学性质研究

研究了溶胶凝胶协同自组装制备大面积高质量SiO₂反蛋白石结构薄膜的方法. 向单分散的聚苯乙烯(PS)胶体溶液中添加SiO₂前驱物溶液,用垂直自组装法一步得到微球空隙中均匀填充有凝胶的 复合PS胶体晶体薄膜,在空气中烧结去除PS后得到SiO₂反蛋白石结构薄膜.通过对添加前驱物溶液比例、 自组装温度以及烧结温度等参数的研究,用不同粒径的PS微球制备了不同孔径的高质量SiO₂反蛋白石结构薄膜. 用扫描电子显微镜和X射线能量色散谱仪对制备得到的薄膜样品进行显微形貌和成分表征,并测试了其透射光谱. 结果表明:溶胶凝胶协同自组装法制备的SiO₂反蛋白石结构薄膜大面积高度有序,孔径可以控制且选择范围宽; 薄膜的透射光谱带隙明显,带隙中心波长与理论计算结果相符.     

Optical quantum transmitter with finesse of 30 at 800-nm central wavelength using microring resonators

A microring resonator (MRR) system incorporating an add/drop system is presented. The finesse of the proposed system can be determined using the full width at half maximum (FWHM) and free spectrum range (FSR) of the generated multiple soliton pulses. The central wavelength of the bright input soliton pulse has been selected as 800 nm, at which a ring system with better sensitivity shows high finesse that is suitable for applications to many optical communication systems such as optical transmitters and sensors. Simulation results show that FSR of 0.3 nm and 1.1 ns and FWHM of 10 pm and 36.6 ps could be obtained. Therefore, a system with finesse of 30 can be obtained; in such a system, the MRR system shows high performance. This system can be used in optical communication networks as a transmitter system for optical soliton pulses with finesse of 30, and theses pulses can be detected via an optical receiver.     

退火对Ga_2O_3薄膜特性的影响

采用金属有机物化学气相沉积法在c面蓝宝石衬底上生长了高质量的β-Ga_2O_3薄膜,并将样品分别在真空、氧气、氮气氛围下退火30 min,研究了各类退火工艺对Ga_2O_3薄膜特性的影响,对退火所得的薄膜进行了X射线衍射、光致发光谱、紫外透射谱和原子力显微镜扫描的研究。结果表明,各类退火工艺均能够优化薄膜的晶体质量和表面形貌,同时有效改善了薄膜的光学性质。其中,氧气退火后的样品在可见光波段透射率高达83%,且吸收边更加陡峭;表面粗糙度降至0.564 nm,其表面更为平整。这些结果说明氧气退火对晶体质量的提高最为显著。氮气、真空退火的样品在光致发光谱中出现365 nm的发光峰,这是大量氧空位的存在导致的。     

SiO2纳米微球表面结构在可见光波段的减反特性

研究了不同尺寸SiO2胶体微球形成纳米结构薄膜的光学传输特性和光子带隙。通过在玻璃基底上自组装透光的SiO2胶体微球形成胶体晶体薄膜, 依据布拉格定律,分析微球尺寸对胶体晶体光子带隙的影响。为实现可见光波段的全方位减反射,提出通过改变胶体粒径将胶体晶体带隙位置移动至紫外波段,理论计算得出当粒径为112 nm,占空比为0.45时能实现可见光波段0.5%的平均反射率。实验结果表明,玻璃基底在400~800 nm间的平均反射率从4.3%降低至0.7%,最小反射率达0.3%。通过控制微球粒径移动光子带隙位置,优化晶体结构参数实现了可见光波段的减反射,有效提高了光学组件对可见光的利用率。     

基于光纤的三维可调胶体光子晶体

用改进的垂直沉积法在光纤端面制备了高质量的SiO₂胶体光子晶体,经过烧结、固化构成胶体光子晶体-光纤结构. 用扫描电子显微镜确定了样品为面心立方密排结构,其密排面平行于光纤基底表面. 利用全光纤传感网络测试了该胶体光子晶体,反射峰中心位于845 nm处,与Bragg理论计算值符合很好. 将该样品浸入不同折射率的液体中,反射光谱的峰值位置随着液体折射率的改变而发生偏移,近似呈线性关系,实现了峰位可调. 对于不同浓度引起的液体折射率的变化,基于光纤的胶体光子晶体结构也能够很好地分辨出来. 关键词： 可调胶体光子晶体 2微球')" href="#">SiO₂微球 Bragg反射 光纤     

池厚对SiO2胶体光子带隙的影响

在薄池中，胶体晶体生长的速度比在厚池中快而且质量好。不同分散度的小球自排的实验结果表明：较差分散度的SiO2小球在超薄池中也能形成质量较好的单昌。光子带隙波长在薄池中有明显的红移，池厚为0.07mm的胶体单晶的带隙波长比池厚为1mm的胶体单晶的带隙波长红移了24nm。     

二氧化硅胶体球自组装光子晶体的研究

光子晶体由于具有光子带隙和光子局域等一系列优异的光学特性而受到了人们广泛的关注。由于采用胶体颗粒自组装法制备光子晶体制备工艺简单,所需要的费用也较低,因此已成为制备可见光至红外波段三维光子晶体的一种简便有效的方法。采用垂直沉积法制得了三维光子晶体薄膜,并用扫描电子显微镜和紫外-可见光-近红外分光光度计对其显微结构和光学特性进行了详细的研究。结果表明,自组装薄膜在三维方向上都具有有序结构,其密排面平行于载波片的表面。制备的光子晶体薄膜具有明显的光子带隙特性,带隙中心波长为956nm。研究了带隙中心波长同入射线与密排面法线夹角之间的变化关系,其结果与理论值吻合得很好。     

Uniform thin films of TiO2 nanoparticles deposited by matrix-assisted pulsed laser evaporation

We report morphological and optical properties of a colloidal TiO₂ nanoparticle film, deposited on a quartz substrate by using the Matrix-Assisted Pulsed Laser Evaporation (MAPLE) technique. Atomic Force Microscopy demonstrated that a good uniformity of the deposition can be obtained. The presence of agglomerates with dimensions of about 1 μm in size was noticed. Form UV-vis transmission spectra, recorded in the 200-800 nm range, the optical constants and the energy gap were determined besides the film thickness. The optical constants resulted in agreement with the values reported in literature for TiO₂ nanoparticle thin films.     

Optical and magneto-optical resonances in nanocorrugated ferromagnetic films

We report here on optical and magneto-optical spectra investigations of nanostructured Co and Ni films deposited on top of polymethyl methacrylate (PMMA) colloidal crystal. Resonant peculiarities have been observed in both spectra; their positions are scaled with the PMMA sphere diameter and depend on incident angle. Asymmetry of the resonance lineshapes as well as change of the direction of magneto-optical rotation has been observed. Both the surface plasmon resonance and the interference between reflections from the colloidal crystal and from the nanostructured film should be considered to explain the obtained results.     

Cu掺杂Ga2O3薄膜的光学性能

采用射频磁控溅射和N2气氛退火处理制备了多晶Ga2O3薄膜和Cu掺杂Ga2O3薄膜.用X射线衍射仪、紫外-可见分光光度计、荧光光谱仪对Ga2O3薄膜和Cu掺杂Ga2O3薄膜的结构和光学性能进行了表征.结果表明,Cu掺杂后Ga2O3薄膜的结晶质量变差,透过率明显降低,吸收率增加,光学带隙减小.本征Ga2O3薄膜在紫外、蓝光和绿光出现了发光带,Cu掺杂后紫外和蓝光发射增强,且在475nm处出现了一个新的发光峰.     

胶体晶体微结构光纤传输特性研究

介绍了胶体晶体微结构光纤的结构, 采用时域有限差分法研究了微结构胶体晶体光纤的传输特性. 建立了该结构的FDTD模型, 计算了其透射谱和不同波长的传输场分布. 搭建了光学系统, 测量了实验制备的胶体晶体微结构光纤的透射谱, 并将其与模拟所得透射谱进行比较, 具有良好的一致性. 胶体晶体微结构光纤的传输场分布结果表明, 胶体晶体在不同波长下改变光纤传输场分布.     

High finesse opto-mechanical cavity with a movable thirty-micron-size mirror

We report on the demonstration of a high finesse micro-optomechanical system and identify potential applications ranging from optical cooling to weak force detection to massive quantum superpositions. The system consists of a high quality diameter flat dielectric mirror cut from a larger substrate with a focused ion beam and attached to an atomic force microscope cantilever. Cavity ring-down measurements performed on a 25 mm long Fabry-Pérot cavity with the 30 microm mirror at one end show an optical finesse of 2100. Numerical calculations show that the finesse is not diffraction limited and that orders of magnitude higher finesse should be possible. A mechanical quality factor of more than 10(5) at pressures below 10(-3) mbar is demonstrated for the cantilever with a mirror attached.     

胶体晶体微结构光纤传输特性研究

介绍了胶体晶体微结构光纤的结构, 采用时域有限差分法研究了微结构胶体晶体光纤的传输特性. 建立了该结构的FDTD模型, 计算了其透射谱和不同波长的传输场分布. 搭建了光学系统, 测量了实验制备的胶体晶体微结构光纤的透射谱, 并将其与模拟所得透射谱进行比较, 具有良好的一致性. 胶体晶体微结构光纤的传输场分布结果表明, 胶体晶体在不同波长下改变光纤传输场分布.     

Solution Lithography for Colloidal Crystal Patterning: Revisiting Flory–Huggins Interaction Parameters and Co-Nonsolvent Systems

For fundamental studies and practical applications, colloidal crystal patterns on substrates are typically fabricated through etching and conventional lithography. However, a wet-chemical based method is necessary for simplifying the procedure, preserving the substrate structure, and reproducibly fabricating the colloidal crystal patterns. The present study demonstrates that colloidal crystal patterns can be conveniently generated using thermodynamic relationships between a polymer colloid and surrounding solvents. Close-packed colloidal monolayers in good solvents that cause colloidal swelling spontaneously transform into non–close-packed crystal patterns when non-solvents that cause their shrinkage replace the good solvents. The colloid diameter in the close-packed monolayer decreases significantly when the polymer in the colloid is passing thermodynamic theta conditions (when Flory–Huggins interaction parameters increase to higher than ≈0.5). The close-packed monolayers also transform into the patterns in co-nonsolvent conditions. The “solution lithography” might be particularly useful for patterning colloids on curved microstructures and plastic/flexible films. The colloidal shapes in the patterns vary with the solvent pairs and substrates. The method does not require special facilities to reproducibly fabricate the patterns. The study further suggests methods simultaneously fixing the patterns. The patterns exhibit anti-reflection properties. Therefore, the solution lithography is applicable to optics, electronics, analytical science, and energy systems.     

通讯波段禁带胶体光子晶体的制备及实验参数研究

采用直径为700nm的二氧化硅微球,通过垂直沉积法在玻璃基片上制备了位于光通讯波段的禁带胶体光子晶体。研究了不同蒸发温度、湿度条件、干燥过程对样品晶体质量的影响。用扫描电子显微镜(SEM)对其形貌进行了观测。实验结果表明,在温度为65℃,相对湿度为70%,缓慢干燥条件下制备出的样品具有较好的晶体质量,晶体在大范围内保持了面心立方(FCC)单晶结构,其(111)面平行于生长基片。     

金属诱导生长与超高真空化学气相沉积方法相结合制备多晶锗硅薄膜

采用金属Ni诱导与超高真空化学气相沉积(UHVCVD)相结合的方法，在热氧化硅衬底上生长了多晶锗硅薄膜.利用X射线衍射(XRD)、场发射扫描电镜(SEM)等对多晶锗硅薄膜的质量、表面形貌进行了测试分析，并就生长参数以及金属Ni对薄膜性能的影响进行了研究.结果表明：1)在420—500℃范围内，金属Ni具有明显的诱导作用；2)Ni层厚度对薄膜质量及形貌的影响使得晶粒尺寸随Ni厚度增加存在一极大值.在Ni层厚度为60nm时，能够获得晶粒尺寸均匀，晶粒大小为500—600nm，结晶质量良好的多晶锗硅薄膜. 关键词： 超高真空化学气相沉积 金属诱导 镍 多晶锗硅     

FCC结构胶体光子晶体的制备及其带隙特性测量

基于对光纤传输特性和胶体光子晶体制备方法的研究,提出了用外加电场控制的方法制备光子带隙位于通讯波段的FCC结构的胶体光子晶体,并用光纤系统测试胶体光子晶体的带隙特性.采用RSOFT模拟了胶体光子晶体的带隙,分析了带隙位于通讯波段时所需的胶体微球的基本参量(微球折射率和直径).采用自组装的方法,用步进电机控制玻璃基片向上的拉升速率.速率为5 μm/s,同时外加一电场.用扫描电镜观测胶体晶体的表面形貌,并设计了单模光纤系统测量胶体光子晶体的带隙特性.测试的透射谱线表明胶体光子晶体的带隙中心波长为1552 nm.测试结果和模拟结果具有很好的一致性,误差只有2 nm.     

退火温度对原子层沉积法制备ZnMgO薄膜结构和光学性能的影响

针对目前关于退火温度对原子层沉积法(ALD)制备ZnMgO薄膜晶体结构和光学性质影响鲜有报道的现象,进行了相应的实验研究分析。采用ALD在石英衬底上制备ZnMgO合金薄膜,对制得的样品在空气中进行不同温度的退火处理。利用X射线多晶衍射仪(XRD)、光致发光谱(PL)和紫外可见(UV-Vis)吸收光谱测试,系统的分析了不同退火温度对ALD法制备ZnMgO薄膜晶体结构和光学性能的影响。XRD测试结果表明：退火温度为600 ℃时,薄膜的晶体质量得到改善,且(100)衍射峰的强度明显增强。结合PL和UV-Vis吸收光谱的测试分析得出：退火温度为600 ℃时,能明显促进薄膜中Mg组分的增加使薄膜的禁带宽度进一步增大。从而说明适当温度的退火处理可有效的改善ZnMgO薄膜的晶体质量及光学特性。     

Microtorus: a high-finesse microcavity with whispering-gallery modes

We demonstrate a 165-mu;m oblate spheroidal microcavity with a free spectral range of 383.7 GHz (3.06 nm), a resonance bandwidth of 23 MHz (quality factor Q approximately 10(7)) at 1550 nm, and finesse F>/=10(4) . The highly oblate spheroidal dielectric microcavity combines a very high Q factor, typical of microspheres, with a vastly reduced number of excited whispering-gallery modes (by 2 orders of magnitude). The very large free spectral range in this novel microcavity-a few hundred gigahertz instead of a few gigahertz as in typical microspheres-is desirable for applications in spectral analysis, narrow-linewidth optical and rf oscillators, and cavity QED.