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1.
Tingyin Ning Cong Chen Yueliang Zhou Heng Lu Dongxiang Zhang Hai Ming Guozhen Yang 《Applied Physics A: Materials Science & Processing》2009,94(3):567-570
CaCu3Ti4O12 (CCTO) thin films were successfully prepared on LaAlO3 substrates by pulsed laser deposition technique. We measured the nonlinear optical susceptibility of the thin films using
Z-scan method at a wavelength of 532 nm with pulse durations of 25 ps and 7 ns. The large values of the third-order nonlinear
optical susceptibility, χ
(3), of the CCTO film were obtained to be 2.79×10−8 esu and 3.30×10−6 esu in picosecond and nanosecond time regimes, respectively, which are among the best results of some representative nonlinear
optical materials. The origin of optical nonlinearity of CCTO films was discussed. The results indicate that the CCTO films
on LaAlO3 substrates are promising candidate materials for applications in nonlinear optical devices. 相似文献
2.
Y. Liu D. Li R.Y. Zhu G.J. You S.X. Qian Y. Yang J.L. Shi 《Applied physics. B, Lasers and optics》2003,76(4):435-439
Au-core CdS-shell composite nanoparticles were synthesized by a direct self-assembly process and integrated into BaTiO3 thin films. Characterization by transmission electron microscopy showed that the average diameter of these composite nanoparticles
was about 8 nm. Using the femtosecond time-resolved optical Kerr effect method, we investigated the third-order nonlinear
optical response of the Au@CdS nanoparticles embedded in the BaTiO3 thin films at a wavelength of 800 nm. An ultrafast nonlinear response and a large effective third-order nonlinear susceptibility
of χ(3)=7.7×10-11 esu were observed. We attributed the enhancement of the third-order optical nonlinearity to a localized electric field effect
originating from the core-shell structure under off-surface-plasmon resonance conditions.
Received: 13 May 2002 / Revised version: 23 October 2002 / Published online: 3 April 2003
RID="*"
ID="*"Corresponding author. Fax: +86-21/6510-4949, E-mail: sxqian@fudan.ac.cn 相似文献
3.
采用脉冲激光沉积技术在Si(100)和熔石英基片上制备了单相的CuO薄膜.通过X射线衍射仪,拉曼光谱仪,场发射扫描电镜和紫外可见光光度计对薄膜的结构,表面形貌和光学性质进行了表征. 场发射扫描电镜结果表明CuO薄膜中晶粒排列致密且分布均匀,其尺寸约为45nm.结合飞秒激光(800nm,50fs)和Z扫描方法测量了薄膜的三阶非线性光学特性,结果表明CuO薄膜具有超快的非线性光学响应且非线性折射率和非线性吸收系数均为负值,其大小分别为-3.96×10-17 m2<
关键词:
CuO薄膜
Z-扫描')" href="#">Z-扫描
三阶光学非线性 相似文献
4.
The nonlinear optical properties of thin films of LaEr(MoO4)3 were studied using a ∼30 ps Nd:YAG laser at 532 nm with a repetition rate of 250 Hz. Closed aperture Z-scan measurement revealed
a negative nonlinearity in the LaEr(MoO4)3. The nonlinear refractive index γ=1.38×10-10 cm2/W and nonlinear absorption coefficient β=16.8×10-6 cm/W were calculated from the Z-scan data. The fluorescent upconversion spectra were recorded with 980 nm excitation. An
optical switching mechanism based on nonlinear absorption is also presented experimentally.
PACS 81.15.Fg; 77.84.Bw; 33.50.Dq; 42.70.Mp 相似文献
5.
Third order nonlinear optical susceptibilities χ<3> of ternary Zn1−xMgxSe and Cd1−xMgxSe crystals have been measured using standard degenerate four-wave mixing (DFWM) method at 532 nm. The nonlinear transmission
technique has been applied to check if our crystals exhibit two-photon absorption. The studied Zn1−xMgxSe and Cd1−xMgxSe solid solutions were grown from the melt by the modified high-pressure Bridgman method. For both crystals the energy gap
increases with increasing Mg content.
In the case of Zn1−xMgxSe, it was found that the value of third order nonlinear optical susceptibility χ<3> decreases with increasing Mg content. An explanation of this behaviour results from the dependence of optical nonlinearities
on the energy band gap Eg of the studied crystals. In the case of Cd1txMgxSe with low content of Mg, no response was observed for the studied wavelength since the energy gap in such crystals is smaller
than the photon energy of the used laser radiation.
It was also found that the value of third order nonlinear optical susceptibility χ<3> for Cd0.70Mg0.30Se is higher than for Zn0.67Mg0.33Se. This behaviour can be understood if one take into consideration that the free carrier concentration in Cd1−xMgxSe samples is about four orders of magnitude higher than that in Zn1txMgxSe ones with comparable Mg content respectively. It is commonly known that when the electric conductivity increases, the values
of nonlinear optical properties increase.
From the performed measurements one can conclude that the incorporation of Mg as constituent into ZnSe and CdSe crystals leads
to a change of the third order nonlinear optical susceptibilities. 相似文献
6.
Qiming Liu Xuan He Ting Hu Chang Gao Yanan Hou Xiujian Zhao 《Applied Physics A: Materials Science & Processing》2011,102(1):245-249
0.56GeS2-0.24Ga2S3-0.2KI (mol%) chalcohalide glass was prepared and second-harmonic generation was observed by the thermal poling process. Second-order
optical nonlinearity in the glass was also investigated by different poling temperature, voltage and time to optimize the
poling parameters to improve χ
(2). The maximum χ
(2) in our study as large as 3.74 pm/V was obtained under the optimized poling condition with 5.2 kV, 260°C and 120 minutes. 相似文献
7.
X.T. Li P.Y. Du H. Ye C.L. Mak K.H. Wong 《Applied Physics A: Materials Science & Processing》2008,92(2):397-400
Textured LixNi2-xO (LNO) thin films have been fabricated on (001)MgO substrates by pulsed laser deposition technique. The as-deposited LNO
films shows a conductivity of 2.5×10-3 Ω m and possess a transmittance of about 35% in the visible region. Subsequent deposition of Sr0.6Ba0.4Nb2O6 (SBN60) thin film on these LNO-coated MgO substrates resulted in a textured SBN layer with a 〈001〉 orientation perpendicular
to the substrate plane. Phi scans on the (221) plane of the SBN layer indicated that the films have two in-plane orientations
with respect to the substrate. The SBN unit cells were rotated in the plane of the film by ± 8.2° as well as ± 45° with respect
to the LNO/MgO substrate. Besides the highly (00l)-orientation, the SBN films also exhibited a dense microstructure as shown
by scanning electron microscopy. The electro-optic coefficient (r33) of the SBN film was measured to be 186 pm/V. On the basis of our results, we have demonstrated that the LNO film can be
used as a buffer layer as well as a transparent bottom electrode for waveguide applications. The SBN/LNO heterostructure is
also a suitable candidate for integrated electro-optics devices.
PACS 42.79.Gn; 42.82.Et; 78.20.Ci 相似文献
8.
V. I. Lukanin D. S. Chunaev A. Ya. Karasik 《Journal of Experimental and Theoretical Physics》2011,113(3):412-421
The nonlinear process of two-photon interband absorption is studied in tungstate and molybdate oxide crystals excited by a
sequence of high-power picosecond pulses with a wavelength of 523.5 nm. The transmission of the crystals is measured for the
excitation pulse intensity up to 100 GW/cm2. The pulse intensity in the crystals initially transparent at a wavelength of 523.5 nm is strongly limited due to two-photon
absorption (TPA), and the reciprocal transmission in PbWO4 and ZnWO4 crystals reaches 50–60. In all crystals, TPA induces long-lived one-photon absorption, which affects the nonlinear process
dynamics and leads to a hysteresis in the dependence of the transmission on the laser excitation intensity. Absorption dichroism
manifests itself in a significant difference in the transmission intensities when the principal orthogonal optical axes of
the crystals are excited. The TPA coefficients are determined during the excitation of two optical axes of the crystals. TPA
coefficients β for the crystals vary over a wide range, namely, from β = 2.4 cm/GW for PbMoO4 to β = 0.14 cm/GW for CaMoO4, and the values of β can differ almost threefold when different optical axes of a crystal are excited. Good agreement is
achieved between the measured intensities limited by TPA and the estimates calculated from the measured nonlinear coefficients.
Stimulated Raman scattering (SRS) upon excitation at a wavelength of 523.5 nm is only detected in two of the four crystals
under study. The experimental results make it possible to explain the suppression of SRS by its competition with TPA, and
the measured nonlinear coefficients are used to estimate this suppression. 相似文献
9.
R. Castro-Beltran G. Ramos-Ortiz C. K. W. Jim J. L. Maldonado M. H?u?ler D. Peralta-Dominguez M. A. Meneses-Nava O. Barbosa-Garcia B. Z. Tang 《Applied physics. B, Lasers and optics》2009,97(2):489-496
The nonlinear optical properties of a hyperbranched polyyne (hb-Polyyne) have been measured at infrared wavelengths by using femtosecond and nanosecond pulsed excitation. This hyperbranched
polyyne exhibited strong and intrinsic (simultaneous) two-photon absorption and upconverted blue fluorescent emission under
femtosecond excitation around 800 nm. The hb-Polyyne in chloroform solution is characterized by a large two-photon absorption cross section of 9068 GM (1GM=10−50 cm4 s) and a fluorescence quantum yield of 0.57. On the other hand, by third-harmonic generation (THG) spectroscopy with nanosecond
excitation, the measured third-order nonlinear susceptibility χ
(3) for solid films of hb-Polyyne ranged from 2.4×10−11 to 6.1×10−11 esu in the spectral range of 1100–1600 nm, with results comparable to the values exhibited by the well-known conjugated polymer
MEH:PPV, but with a much better transparency for visible wavelengths. 相似文献
10.
V. Hinkov C.T. Lin M. Raichle B. Keimer Y. Sidis P. Bourges S. Pailhès A. Ivanov 《The European physical journal. Special topics》2010,188(1):113-129
In this paper, we first give a concise overview of recent experimental and theoretical work dealing with “electronic liquid-crystal
states” which spontaneously break different symmetries of the CuO2 layers of high-T
c cuprates, with an emphasis on evidence in the spin excitation spectrum. Then we describe the importance of using twin-free
samples to look for evidence for fourfold symmetry breaking in the spectrum and explain the preparation procedure to obtain
such samples. We present inelastic neutron scattering results for moderately underdoped YBa2Cu3O6.6(T
c = 61 K) and nearly optimally doped YBa2Cu3O6.85(T
c = 89 K). In YBa2Cu3O6.6, the dispersion topology changes when heating above T
c from an hourglass shape with constricted, commensurate resonance peak to a “Y”-shape without resonance anomaly. This change,
and the fact that the low-energy signal above T
c can be described by an incommensurate, quasi-one-dimensional distribution, indicates a competition of superconductivity with
an electronic liquid-crystal state. We then show a striking analogy between the difference signal I(5 K) − I(70 K) and the downward dispersing resonance mode in YBa2Cu3O6.85. We therefore argue that a resonance mode only emerges below T
c, irrespective of the doping level. We finally discuss the implications of our results for the different scenarios invoked
to explain the electronic liquid-crystal state in cuprates. 相似文献
11.
K. Koshiba T. Honma Y. Benino T. Komatsu 《Applied Physics A: Materials Science & Processing》2007,89(4):981-986
Dots and lines consisting of nonlinear optical GdxBi1-xBO3 crystals were patterned on the surface of CuO-doped Gd2O3-Bi2O3-B2O3 glass by heat-assisted (200 °C) Nd:YAG laser irradiations with a wavelength of λ=1064 nm, where the laser energy absorbed
by Cu2+ is converted to the local heating of the surrounding Cu2+. The surface morphology and orientation of crystals in the patterned lines were clarified from confocal scanning laser microscope
observations and polarized micro-Raman scattering spectra. Crystal lines with periodic bumps (i.e., ladder-shape like lines)
were patterned by laser irradiations with a power of 0.79 W and a scanning speed of 60 μm/s, and the orientation of GdxBi1-xBO3 crystals in the lines was proposed. The present study demonstrates that the combination of Cu2+ and continuous wave Nd:YAG laser with λ=1064 nm is effective in inducting crystallization of oxide glasses. The mechanism
of laser-induced crystallization in glass has also been discussed.
PACS 61.43.Fs; 42.70.Mp; 68.35.Bs; 78.30.-j; 79.20.Ds 相似文献
12.
A nonlinear optical method has been proposed for probing the evolution of a plasma and energy transfer processes in the microvolume
of a transparent dielectric using the third-harmonic probe signal. The electron self-trapping time has been estimated as t = 150 ± 80 fs. A decrease in the third-harmonic probe signal has been detected at the picosecond time scale; this decrease
can be attributed to a change in the third-order susceptibility χ(3) of a fused silica sample modified by laser radiation. 相似文献
13.
A. Li L. Sun Z. Zheng Q. Lü W. Wu W. Liu Y. Yang T. Lü 《Applied physics. B, Lasers and optics》2008,90(1):29-34
The results of the spectroscopic analysis of transition strengths for Er3+ ions in a series of Hf:Er:LiNbO3 crystals with variable Hf content and fixed Er content are reported. Unpolarized UV-VIS-NIR absorption spectra, upconversion
fluorescence spectra excited at 800 nm, and microsecond time-resolved spectra excited at 400 nm and 800 nm by 800 nm femtosecond
laser were measured at room temperature. The HfO2 incorporation has influence on Er3+ radiative lifetimes, and fluorescence branching ratios. For Hf(4 mol %):Er(1 mol %):LiNbO3, Ω2=2.63×10-20 cm2, Ω4=2.86×10-20 cm2, and Ω6=0.72×10-20 cm2. Ω2<Ω4 is contrary to the Er3+ general trend of Ω2>Ω4>Ω6 when the Hf content is below its threshold concentration. In addition, the sum of Ω increases with the Hf content when the
HfO2 content below 6 mol % is unfamiliar. The upconversion mechanism is discussed in this work.
PACS 71.20.Eh; 77.84.Dy; 42.62.Fi; 42.65.Ky 相似文献
14.
A Cu2+-doped single crystal of catena-trans-bis(N-(2-hydroxyethyl)-ethylenediamine) zinc(II)-tetra-m-cyanopaladate(II) [ZnPd(CN)4(C4H12N2O2)] complex has been investigated by electron paramagnetic resonance (EPR) technique at room temperature. EPR spectra indicate
that Cu2+ ions substitute for magnetically equivalent Zn2+ ions and form octahedral complexes in [ZnPd(CN)4(C4H12N2O2)] hosts. The crystal field affecting the Cu2+ ion is nearly axial. The optical absorption studies show two bands at 322 nm (30864 cm−1) and 634 nm (15337 cm−1) which confirm the axial symmetry. The spin Hamiltonian parameters and the relevant wave function are determined. 相似文献
15.
The layered LiNi0.5Mn0.47Al0.03O2 was synthesized by wet chemical method and characterized by X-ray diffraction and analysis of magnetic measurements. The
powders adopted the α-NaFeO2 structure. This substitution of Al for Mn promotes the formation of Li(Ni0.472+Ni0.033+Mn0.474+Al0.033+)O2 structures and induces an increase in the average oxidation state of Ni, thereby leading to the shrinkage of the lattice
unit cell. The concentration of antisite defects in which Ni2+ occupies the (3a) Li lattice sites in the Wyckoff notation has been estimated from the ferromagnetic Ni2+(3a)–Mn4+(3b) pairing observed below 140 K. The substitution of 3% Al for Mn reduces the amount of antisite defects from 7% to 6.4–6.5%.
The analysis of the magnetic properties in the paramagnetic phase in the framework of the Curie–Weiss law agrees well with
the combination of Ni2+ (S = 1), Ni3+ (S = 1/2) and Mn4+ (S = 3/2) spin-only values. Delithiation has been made by the use of K2S2O8. According to this process, known to be softer than the electrochemical one, the nickel ions in the (3b) sites are converted into Ni4+ in the high spin configuration, while Ni2+(3a)–Mn4+(3b) ferromagnetic pairs remain, as the Li+(3b) ions linked to the Ni2+(3a) ions in the antisite defects are not removed. The results show that the antisite defect is surrounded by Mn4+ ions, implying the nonuniform distribution of the cations in agreement with previous NMR and neutron experiments. 相似文献
16.
V. I. Gerasimova A. A. Antoshkov Yu. S. Zavorotny D. A. Lemenovskii 《Journal of Applied Spectroscopy》2012,79(2):203-210
Optical properties (photoluminescence and absorption) of Eu(bta)3(B) n (B = H2O or 1,10-phenanthroline) polycrystalline powders and fluoroacrylate polymers (FAPs) impregnated with these compounds using supercritical CO2 (SC CO2) were investigated. It was established that impregnation of Eu(bta)3phen into the FAPs using an SC CO2 solution was difficult to achieve. The type of B (ancillary ligand) and the polymer matrix were shown to influence the temperature quenching of photoluminescence of Eu3+ ions in the range 25–100°C. A comparative analysis of quantum yields (λex = 300 and 380 nm) and photoluminescence decay times (λex = 337.1 nm) for Eu(bta)3B n and for Eu(bta)3B n -doped FAPs was performed. 相似文献
17.
Single tracks and pairs of tracks are written in the volume of Pr-doped LiYF4-crystals using tightly focused femtosecond laser radiation (λ=1045 nm, τ
p=400–500 fs, f=0.1–1 MHz). Waveguiding between the tracks is demonstrated and optimized by varying the distance between the tracks and the
laser writing conditions. The stress-induced guiding mechanism is explained based on TEM, interference microscopy, near-field
and far-field measurements. It is shown that the single-crystalline material is getting poly-crystalline under femtosecond
laser irradiation. By measuring the lifetime of the 3P1→3H5 transition and the emission spectrum at excitation with λ=444 nm, no influence on these properties of the guided light is observed. This possibly enables the realization of a channel
waveguide laser in the visible spectral range. 相似文献
18.
V. O. Kompanets V. B. Laptev A. A. Makarov S. V. Pigulsky E. A. Ryabov S. V. Chekalin 《JETP Letters》2010,92(3):135-139
The dynamics of multiphoton excitation of (CF3)2CCO molecules has been investigated under the condition of resonant action of femtosecond infrared laser radiation on the
ν1 vibrational mode of the C=C=O bond. It has been shown that the mode-selective excitation of this vibration occurs up to the
ν = 6 level. The kinetics of the subsequent intramolecular vibrational energy redistribution from the ν1 mode has been measured. A value of 5 ± 0.3 ps has been obtained for the characteristic time of this process. 相似文献
19.
Large third-order nonlinear optical susceptibility of Au-Al2O3 composite films near the resonant frequency 总被引:2,自引:0,他引:2
2 O3 composite films with high Au concentrations (30%–60% in volume fraction) were prepared by reactive co-sputtering and post
rapidly thermal annealing. The structure of the films and the size distributions of the Au nanoclusters were examined by TEM,
and the third-order nonlinear optical susceptibility χ(3) was measured by degenerated four-wave mixing using a 70-ps pulse laser at 532 nm. The maximum value of the χ(3) was about 1.2×10-6 esu in the annealed films and occurred at around 45% Au concentration. The figure of merit, χ(3)/α (α is the absorption coefficient), has a value of 7×10-12 esu cm over a wide range of Au concentrations.
Received: 23 July 1997 相似文献
20.
V. M. Marchenko L. D. Iskhakova A. V. Kir’yanov V. M. Mashinsky N. M. Karatun E. M. Sholokhov 《Laser Physics》2012,22(1):177-183
Yb2O3 polycrystals with a size of up to 10 mm are synthesized using the sintering and melting of the ultrapure Yb2O3 powders by the CO2-laser radiation with the power P
L ≤ 100 W at the wavelength λ = 10.6 μm at the melting point T
m = 2703 K, forming due to surface tension in melt, and crystallization in air. The analysis of the polycrystal microstructure
using the methods of optical and electron microscopy and X- ray diffractometry shows that perfect oxide crystallites are formed
in the course of crystallization after melting-through. The transformation of the luminescence and selective heat radiation
(SHR) spectra of the Yb2O3 polycrystals is studied under the resonant excitation at λ ≈ 975 nm using a laser diode and the laser heating at the wavelength
λ = 10.6 μm. When the resonant excitation power of the Yb3+ ions increases from 0.15 to 4.5 W, the Stokes luminescence of the Yb2O3 polycrystals is sequentially transformed into SHR and the thermal radiation of the crystal lattice. The transformation of
the emission spectra of the Yb2O3 polycrystals with an increase in the laser heating intensity by about four orders of magnitude can be represented as the
low-temperature heat radiation, spectral burst of the thermodynamically nonequilibrium SHR of the Yb3+ ions, and the high-temperature radiation of the crystal lattice. The temperature dependence of the luminescence spectra and
SHR of the Yb2O3 polycrystals on the intensity of the laser and laser-thermal excitation and the concentration quenching of the Yb3+ luminescence in oxides indicate the key role of the interaction of the f-electron shell of the Yb3+ ions with the natural oscillations of the crystal lattice in the processes of the multiphonon excitation and nonradiative
(multiphonon) and radiative (vibronic) relaxation. 相似文献