共查询到20条相似文献,搜索用时 31 毫秒
1.
Ma W Feng B Ren Y Zeng Q Niu Z Li J Zhang X Dong H Zhou W Xie S 《Journal of nanoscience and nanotechnology》2010,10(11):7333-7335
Large third-order optical nonlinearity is observed in single-walled carbon nanotube (SWNT) films that are directly synthesized by CVD method rather than post-deposited from solution. Through z-scan method, the third-order nonlinear susceptibility (chi(3)) is measured, and the |Im chi(3)| is 1.8 x 10(-7) esu at 1064 nm, which is among the highest reported values for optical nonlinear materials. Combined with their transparent morphology and ultrafast carrier relaxation time, our results indicate the promising prospect of directly synthesized SWNT films as saturable absorbers using in mode-lock lasers or ultrafast switching materials in optical telecommunications. 相似文献
2.
Composite thin films Au:BaTiO3, comprising nanometer-sized gold particles embedded in barium titanate matrices, were synthesized on MgO (100) substrates with the pulsed laser deposition technique. The nanostructure of the films and the size distributions of the Au particles were analyzed by high-resolution transmission electron microscopy. Crystal lattice fringes from the Au nanocrystals and the BaTiO3 matrices were observed. The nonlinear optical properties of the Au:BaTiO3 films were measured with the z-scan method at a wavelength of 532 nm, which was closed to the surface plasmon resonance of nanoscale Au particles. The features of the closed-aperture z-scan transmittance curves were affected by the ratio, which increased greatly at a high metal concentration, of the imaginary part to the real part of the third-order nonlinear susceptibility chi(3). 相似文献
3.
Effect of Surface Roughness on Laser Induced Nonlinear Optical Properties of Annealed ZnO Thin Films
Variation of nonlinear optical properties with surface roughness of ZnO thin films deposited on corning glass substrates at different annealing temperature(TA) was reported.The films were characterized by X-ray diffraction(XRD),UV-Vis-NIR transmission and single beam z-scan technique using second harmonics of Nd:YAG laser.Surface morphology of the samples was investigated by atomic force microscopy(AFM).Surface roughness was found minimum(8.4 nm) for ZnO sample annealed at 450 ℃.The nonlinear optical properties(NLO) were found to be dependent on surface roughness and the highest value of third order nonlinear susceptibility(χ~(3)=4.3×10~(-7) esu) was obtained for ZnO at TA 450 ℃. 相似文献
4.
We present the studies on third-order nonlinear optical properties of Al doped ZnO thin films irradiated with electron beam at different dose rate. Al doped ZnO thin films were deposited on a glass substrate by spray pyrolysis deposition technique. The thin films were irradiated using the 8 MeV electron beam from microtron ranging from 1 kG y to 5 kG y. Nonlinear optical studies were carried out by employing the single beam Z-scan technique to determine the sign and magnitude of absorptive and refractive nonlinearities of the irradiated thin films. Continuous wave He–Ne laser operating at 633 nm was used as source of excitation. The open aperture Z-scan measurements indicated the sample displays reverse saturable absorption (RSA) process. The negative sign of the nonlinear refractive index n2 was noted from the closed aperture Z-scan measurements indicates, the films exhibit self-defocusing property due to thermal nonlinearity. The third-order nonlinear optical susceptibility χ(3) varies from 8.17 × 10−5 esu to 1.39 × 10−3 esu with increase in electron beam irradiation. The present study reveals that the irradiation of electron beam leads to significant changes in the third-order optical nonlinearity. Al doped ZnO displays good optical power handling capability with optical clamping of about ∼5 mW. The irradiation study endorses that the Al doped ZnO under investigation is a promising candidate photonic device applications such as all-optical power limiting. 相似文献
5.
Nanocomposite thin films consisting of nanometer-sized Ag particles embedded in amorphous Ba0.5Sr0.5TiO3 matrix were prepared on fused silica substrates by an alternating pulsed laser deposition method. Their optical nonlinearities have been studied using the Z-scan method. The surface plasmon resonance (SPR) peak shifts to red and increases with the increasing the volume fraction of Ag in the nanocomposite films. The magnitude of the third-order nonlinear susceptibility of the nanocomposite with an Ag volume fraction of 3.3% was calculated to be approximately 2 x 10(-8) esu at the SPR wavelength. 相似文献
6.
7.
BaTiO3基Au纳米颗粒复合薄膜的制备及其光学性质研究 总被引:1,自引:1,他引:0
采用溶胶-凝胶(sol-gel)方法,成功的将高体积面分比的Au纳米颗粒复合到BaTiO3的非晶薄膜中,并对其光学性质进行了研究。用XRD、TEM、椭偏仪、吸收光谱、光克尔效应OKE(Optical Kerr Effcet)方法对薄膜进行了表征和测试。从吸收光谱观察到表面等离子体共振SPR(Surface Plasma Resonance)峰随热处理温度升高而红移的现象。光学非线性测试表明薄膜具有高的三阶非线性极化率Χ^(3)和超快的响应时间。 相似文献
8.
Fahimeh Abrinaei Marzieh Shirazi 《Journal of Materials Science: Materials in Electronics》2017,28(23):17541-17550
In the present study, it has been reported on the effect of Al doping on linear and nonlinear optical properties of ZnO thin films synthesized by spray pyrolysis method. The structural properties of ZnO thin films with different Al doping levels (0–4 wt%) were analyzed using X-ray diffraction (XRD). The results obtained from XRD analysis indicated that the grain size decreased as the Al doping value increased. The UV–Vis diffused refraction spectroscopy was used for calculation of band gap. The optical band gap of Al-doped ZnO (AZO) thin films is increased from 3.26 to 3.31 eV with increasing the Al content from 0 to 4 wt%. The measurements of nonlinear optical properties of AZO thin films have been performed using a nanosecond Nd:YAG pulse laser at 532 nm by the Z-scan technique. The undoped ZnO thin film exhibits reverse saturation absorption (RSA) whereas the AZO thin films exhibit saturation absorption (SA) that shows RSA to SA process with adding Al to ZnO structure under laser irradiation. On the other hand, all the films showed a self-defocusing phenomenon because the photons of laser stay on below the absorption edge of the ZnO and AZO films. The third-order nonlinear optical susceptibility, χ(3), of AZO thin films, was varied from of the order of 10?5–10?4 esu. The results suggest that AZO thin films may be promising candidates for nonlinear optical applications. 相似文献
9.
Wenjian Leng Chuanren Yang Hong Ji Jihua Zhang Jinlong Tang Hongwei Chen Lifeng Gao 《Journal of Materials Science: Materials in Electronics》2007,18(8):887-892
Linear and nonlinear optical properties of (Pb,La)(Zr,Ti)O3 (PLZT) ferroelectric thin films were presented in this paper. The PLZT ferroelectric thin films have been in situ grown on
quartz substrates by radio-frequency (RF) magnetron sputtering at 650 °C. Their crystalline structure and surface morphologies
were examined by X-ray diffraction and atomic force microscopy, respectively. It can be found that the PLZT thin films exhibit
well-crystallized perovskite structure and good surface morphology. The fundamental optical constants (the band gap energy,
linear refractive index, and linear absorption coefficient) were obtained through the optical transmittance measurements.
A Z-scan technique was used to investigate the optical nonlinearity of the PLZT thin films on quartz substrates. The films display
the strong third-order nonlinear optical effect. A large and negative nonlinear refractive index n
2 is determined to be 1.21 × 10−6 esu for the PLZT thin films. All results show that the PLZT ferroelectric thin films have potential applications in optical
limiting, switching, and modulated-type optical devices. 相似文献
10.
Satellite-patterns aggregate structures of gold nanoparticles were fabricated by the inducing pi-pi stacking interactions. The self-assembly process of satellite-patterns was tuned by the controlling ligand exchange on the surface of spherical gold nanoparticles, which provide a novel concept and an efficient method for controlling self-assembly of gold nanoparticles. With increasing the porphyrin alkanethiol ratio (r) of gold nanoparticles, the self-assembly induces to form the larger satellite-structures. The study indicates that exchange process of tetra-n-octylammonium bromide molecules and porphyrin alkanethiol molecules results in the formation of satellite-pattern structures with topological features. Nonlinear optical properties of porphyrin alkanethiol capped gold nanoparticles of toluene solution were measured using the Z-scan technique, and its third-order nonlinear optical susceptibility (chi(3)) is calculated as 0.9 x 10(-13) esu, presented the third-order nonlinear optical properties. The well-ordered assembly of gold nanoparticles exhibits controlled the third-order nonlinear optical properties, which can be enhanced with the increasing of the porphyrin alkanethiol ratio in systems. 相似文献
11.
S. Kannappan R. Liyakath J. Tatsugi 《Journal of Materials Science: Materials in Electronics》2016,27(9):8973-8979
We report the morphologies and the bulk film effect on regioregular poly(3-dodecylthiophene) [RR-P3DDT] thin films fabricated with different concentrations (0.1, 0.2, 0.4 wt%) by drop-casting method using chloroform as a solvent and fused quartz glass as substrate. The measured thicknesses of the films were 220, 340 and 600 nm. The thin films were characterized by UV–Vis spectra and X-ray diffraction. The surface morphology of the thin film (600 nm) was analyzed using atomic force microscopy. The third order nonlinear susceptibility characteristics of the films were measured using Maker fringes method. These films exhibit efficient THG bulk effect with a maximum χ3 value of 1.41 × 10?10 esu obtained for 0.4 wt% concentration of RR-P3DDT revealing that this material is potentially suited for fabricating optical limiters. 相似文献
12.
We fabricated aluminum fluoride (AlF(3)) thin films by pulsed DC magnetron sputtering with various CF(4) flow rates and sputtering powers. Our method is distinct from the conventional deposition process in that we used inexpensive Al (99.99% purity) as the target instead of an expensive fluoride compound. The optical properties and microstructure of the thin films were examined. The optical quality of AlF(3) thin films deposited at a 20 W sputtering power and injected 110 SCCM (SCCM denotes cubic centimeters per minute at standard temperature and pressure) CF(4) flow at room temperature showed improvement with an extinction coefficient of less than 7 x 10(-4) at 193 nm. The deposition of AlF(3) thin films at different substrate temperatures and annealed by UV light was also investigated. 相似文献
13.
The third-order nonlinear optical properties of sol-gel-derived V(2)O(5), Nb(2)O(5), and Ta(2)O(5) thin films have been investigated by the third-harmonic-generation method, and the effect of the metal-oxygen bond length on the third-order nonlinear optical susceptibility χ((3)) has been examined. The χ((3)) values of V(2)O(5), Nb(2)O(5), and Ta(2)O(5) thin films were 1.1 × 10(-11), 1.3 × 10(-12), and 6.1 × 10(-13) esu, respectively, which corresponds to an increase in the average bond length I(b) of the order of V-O (I(b) = 0.183 nm), Nb-O (I(b) = 0.200 nm), and Ta-O (I(b) = 0.204 nm). The current and previous results indicate that χ((3)) of these transition metal oxides with the empty d orbitals is dominated mainly by the metal-oxygen bond length rather than the valence of the metal cation. It is predicted on the basis of Lines' model that transition metal oxides with the shortest I(b) exhibit the highest χ((3)), whereas nontransition metal oxides with the longest I(b) exhibit the highest χ((3)). 相似文献
14.
The inherent optical nonlinearities of thin silver films 总被引:1,自引:0,他引:1
Thin Ag films with the thickness of 80 Å were prepared by pulsed laser deposition technique. The films were grown on MgO(1 0 0) substrates under the nitrogen pressure of 5.0 Pa at room temperature. The surface images of the films were observed by atomic force microscopy. The linear optical properties of the films were studied in the wavelength range of 300–800 nm. The inherent third-order nonlinear optical responses coming from the silver material itself were determined by z-scan method at the wavelength of 532 nm with laser duration of 10 ns. The significant optical nonlinearities of the pure thin Ag films were determined to have the real and imaginary parts of the third-order nonlinear optical susceptibility (χ(3)) as 2.49 × 10−8 and 7.16 × 10−9 esu, respectively. The obtained χ(3) value of Ag films was about one order of magnitude larger than that of Ag colloids. 相似文献
15.
Ultrafast optical nonlinearity of titanylphthalocyanine films 总被引:1,自引:0,他引:1
Guohong Ma Lijun Guo Jun Mi Ye Liu Shixiong Qian Daocheng Pan Yue Huang 《Thin solid films》2002,410(1-2):205-211
The optical properties of titanylphthalocyanine (TiOPc) thin film fabricated by physical jet deposition technique were investigated by using absorption, femtosecond (fs) optical Kerr effect (OKE) and fs pump–probe techniques. The third-order nonlinear optical susceptibility of TiOPc film was measured to be 3×10−10 esu. The OKE response of TiOPc films shows a decay process with subpicosecond time constant, demonstrating that the excited state of TiOPc molecule has little contribution to the photo-induced birefringence. From the fs pump–probe experiment, a complicated decay behavior with three decay components was observed, which originates from the contribution of exciton–exciton annihilation process, the enhanced intersystem crossing process and the relaxation of the triplet state. 相似文献
16.
Using phase-matched third-harmonic generation we determine the effective nonlinear susceptibilities in Hg2Cl2 (Calomel) to /chi(3)eff,I/ = 4.5 x 10(-22) m2V(-2) and /chi(3)eff,II/ = 9.7 x 10(-22) m2V(-2) for type I and type II phase matching, respectively. The type III phase matching uses the same tensor components as type I and is deduced to be /chi(3)eff,III/ approximately equal to 1.5 x 10(-22) m2V(-2). The effective third-order susceptibilities of Hg2Cl2 are two orders of magnitude higher than those of CaCO3, and the tensor components chi11 - 3chi18 exceed the components of ADP by a factor of 5. These measurements demonstrate that Calomel might be a promising material to be used for nonlinear optical devices. 相似文献
17.
设计合成了3个新的含2-芳基-1H-咪唑并[4,5-f][1,10]菲咯啉的Ni(Ⅱ)配合物,用UV、IR、MS和元素分析进行了表征。采用飞秒激光,运用简并四波混频法,研究了Ni(Ⅱ)配合物在非共振状态下的三阶非线性光学性能。它们的三阶非线性光学极化率χ(3)为(3.99~4.36)×10-13esu,非线性折射率n2为(7.33~8.03)×10-12esu,分子二阶超极化率γ为(3.98~4.37)×10-31esu,响应时间τ为50~86fs。探索了配合物的分子结构对三阶非线性光学性能的影响。结果表明扩展π电子共轭体系,增强非平面分子内电荷转移等因素有利于获得较大的三阶光学非线性。 相似文献
18.
SrBi2Nb2O9 (SBN) thin films with a single phase of layered perovskite structure have been fabricated on fused quartz substrates at room temperature by pulsed laser deposition. The XRD and AFM analysis indicated that the films had better crystallinity, less rough surface morphology, and larger grain size with increasing oxygen pressure. The nonlinear optical properties of the samples were determined using a single beam Z-scan technique at a laser wavelength of 532 nm with laser duration of 25 ps. The real and imaginary parts of the third-order nonlinear optical susceptibility χ(3) of the films were measured to be 3.18 × 10− 8 esu and 5.94 × 10− 9 esu, respectively. 相似文献
19.
以MgO∶Ga_2O_3∶ZnO(2%∶2%∶96%,质量分数)陶瓷靶作为溅射源,采用磁控溅射技术在石英玻璃衬底上制备了镁镓共掺氧化锌(MGZO)透明半导体薄膜。采用XRD、SEM、霍尔效应仪和分光光度计对MGZO薄膜进行测试表征,研究了溅射压强对MGZO薄膜晶体结构、电学性质和光学性能的影响。结果表明:所有MGZO薄膜均为六角纤锌矿结构并具有(002)择优取向生长特性,溅射压强对薄膜晶体结构和光电性能有明显影响,但几乎不影响其直接光学能隙(3.41~3.44eV)。当溅射压强为3.5Pa时,MGZO薄膜的结晶质量最好、张应力最小(8.29×10-2 GPa)、电阻率最低(1.62×10-3Ω·cm)、可见光区平均透过率最高(87.8%)、品质因数最大(4.76×103Ω~(-1)·cm~(-1)),具有最好的光电综合性能。 相似文献
20.
采用热丝和射频等离子体辅助化学气相沉积方法(HF-PECVD),以单晶硅为衬底在低温(< 500℃)条件下沉积氮化硼(BN)薄膜材料.通过傅立叶变换红外光谱(FTIR)、 X射线衍射(XRD)及扫描电镜(SEM)对薄膜样品的组成和结构进行了分析,探讨了温度和等离子体对沉积BN薄膜的影响.此外,用紫外-可见光分光光度计(UV)测试了石英衬底上生长磷掺杂氮化硼(BPXN1-X)薄膜样品的紫外吸收特征,分析了磷掺杂对 BN光学能隙的调节作用以及 BPXN1-X薄膜在紫外空间探测领域的应用前景.结果表明,以单晶硅和光学石英玻璃为衬底在低温条件下用 HF-PECVD方法可以沉积较高质量的 BN薄膜,BN的光学能隙宽度通过磷的掺杂可以得到连续调节,在紫外空间光探测领域具有很大的应用潜力. 相似文献