共查询到20条相似文献,搜索用时 15 毫秒
1.
S. Vijayakumar Adithya Adhikari Balakrishna Kalluraya K. Chandrasekharan 《Optical Materials》2009,31(11):1564-1569
The nonlinear optical properties of hydrazones substituted with different donor groups were studied using single beam Z-scan technique with nanosecond laser pulses at 532 nm. The nonlinear response in these molecules was found to increase with increase in the donor strength of the substituted group. The χ(3) value of these molecules is found to be of the order of 10−13 esu. The nonlinear refractive index (n2) of the samples is found to be negative and the largest value of n2 obtained for the strong donor-substituted molecule is −8.83 × 10−11 esu. All samples show good optical limiting behavior at 532 nm. The best optical limiting behavior was observed with the molecule substituted by a strong electron donor. 相似文献
2.
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
3.
Fluorescence and nonlinear optical properties of non-aggregating hexadeca-substituted phthalocyanine
Hacene Manaa Abdullah Al Mulla Saad Makhseed Moyyad Al-sawah Jacob Samuel 《Optical Materials》2009,32(1):108-114
Highly non-aggregating hexadeca-substituted phthalocyanine (Pc) complexes were prepared and their fluorescence and nonlinear optical properties were studied. Three visible fluorescence bands were observed when the Pc complexes were excited at 355 nm and found to be concentration dependent. They are attributed to the optical transitions S2 → S0 at 415 nm, T2 → T1 at 630 nm, and S2 → S1 at 755 nm. Nonlinear absorptive and refractive effects were measured with the help of Z-scan technique. Saturation absorption was observed at 632.8 nm where the nonlinear absorption coefficient is found to be very large (β = −2.8 × 10−2 cm/W) and the refractive nonlinear coefficient γ = −9.5 × 10−11 cm2/W. In the transparency domain at 532 nm, reverse absorption saturation is observed and β and γ are found to be 17.5 and 15.5 times smaller, respectively. Optical limiting performances are measured in the absorption and transparency domains. Purely refractive-based optical limiting at 632.8 nm is found to have a threshold of 0.16 kW/cm2, lower than the reverse absorption saturation and refractive-based optical limiting of 0.90 kW/cm2 at 532 nm. 相似文献
4.
Xiangling Ren Xianwei Meng Fangqiong Tang Lin Zhang 《Materials science & engineering. C, Materials for biological applications》2009,29(7):2234-2238
In this paper, glucose biosensor is fabricated with immobilization of glucose oxidase (GOx) in platinum and silica sol. The glucose biosensor combined with Pt and SiO2 nanoparticles could make full use of the properties of nanoparticles. A set of experimental results indicates that the current response for the enzyme electrode containing platinum and silica nanoparticles increases from 0.32 µA cm− 2 to 33 µA cm− 2 in the solution of 10 mM β-D-glucose. The linear range is 3 × 10− 5 to 3.8 × 10− 3 M with a detection limit of 2 × 10− 5 M at 3σ. The effects of the various volume ratios of Pt and SiO2 sols with respect to the current response and the stability of the enzyme electrodes are studied. 相似文献
5.
Employing the single beam Z-scan technique with nanosecond laser pulses at 532 nm, the refractive and absorptive nonlinearities of donor and acceptor substituted (2E)-1-(3,4-dimethoxyphenyl)-3-phenylprop-2-en-1-one have been studied. The sign of the nonlinear index of refraction (n 2) is found to be negative and the magnitude of n 2 is in the order of 10?11 esu. The second-order molecular hyperpolarizability (γh) is calculated to be in the order of 10?32 esu. The variation of nonlinear absorption coefficient (βeff) with input intensity (I 0) is studied and the nonlinear absorption mechanism is found to be reverse saturable absorption (RSA). The enhancement of nonlinearity due to the donor and acceptor substitution is in accordance with the variation in π electron delocalization in the molecules. The compounds exhibit good optical limiting as well. 相似文献
6.
Guojian Wang Xiumei Han Mingjun Song Guofu Wang Xifa Long 《Materials Letters》2006,60(29-30):3710-3713
(Ba0.32Sr0.68)5Nb4O15 crystal with sizes of Ø 17 × 35 mm was grown successfully by Czochralski technique method. The thermal anisotropy was discussed. The principal coefficients of thermal expansion along (100), (010), (001) directions were precisely measured to be 1.308 × 10− 5, 1.288 × 10− 5, 1.478 × 10− 5 K− 1, respectively. Its optical transparency range has been measured and found to span from 323 to 5500 nm. The bands present in the IR spectra were identified and assigned to the corresponding vibration modes of NbO6 anions. 相似文献
7.
Youyi Sun Yaqing Liu Guizhe zhao Xing Zhou Qijin Zhang Yan Deng 《Materials Chemistry and Physics》2008,111(2-3):301-304
The functional group of sulfur was introduced into the PMMA terminus by the reversible addition-fragmentation transfer (RAFT) technique and the PMMA/Ag nanocomposite film was prepared by the in situ synthetic method. The third-order nonlinear optical properties of the material were further investigated by the Z-scan technique. The result shows that the χ(3) nonlinearity of the material depend on the doped content of Ag nanoparticles and is obtained to be 6.22 × 10−9 esu at the content of 2.4 wt%. Furthermore, it is found that the material has the potential application on optical switcher at the content of 0.8 wt%. 相似文献
8.
12CaO·7Al2O3 electride (C12A7:e−) doped indium tin oxide (ITO) (ITO:C12A7:e−) thin films were fabricated on a glass substrate by an RF magnetron co-sputtering system with increasing number of C12A7:e− chips (from 1 to 7) and at various oxygen partial pressure ratios. The optical transmittance of the ITO:C12A7:e− thin film was higher than 70% in the visible wavelength region. In the electrical properties of the thin film, a decrease of the carrier concentration from 2.6 × 1020 cm− 3 to 2.1 × 1018 cm− 3 and increase of the resistivity from 1.4 × 10− 3 Ω cm to 4.1 × 10− 1 Ω cm were observed with increasing number of C12A7:e− chips and oxygen partial pressure ratios. It was also observed that the Hall mobility was decreased from 17.27 cm2·V− 1·s− 1 to 5.13 cm2·V− 1·s− 1. The work function of the ITO thin film was reduced by doping it with C12A7:e−. 相似文献
9.
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
10.
We use a new in-house, large area and automated deposition system: the usable deposition area is 410 × 520 mm with RF-frequency of 40 MHz. We deposit intrinsic a-Si:H layer on flat p-type or n-type c-Si wafers after performing an HF dip. The overall recombination of these double-side passivated c-Si wafers is measured with an effective lifetime measurement set-up. We pay particular attention to the uniformity of the passivation obtained on the whole deposition area.We point out a major role of hydrogen dilution on quality of c-Si passivation. Excellent uniformity is obtained on the whole area with implied open-circuit voltages (Voc) in a ± 1.5% range. We achieve excellent passivation with overall lifetimes approaching 7 ms (at Δn ≈ 4.5·1014 cm− 3) resulting in implied Voc of 708 mV on p-type c-Si; and lifetimes superior to 4.7 ms resulting in implied Voc of 726 mV on n-type c-Si (Seff less than 2 cm/s for both). These results open the way to very high efficiency heterojunction solar cell fabrication in large area reactors. 相似文献
11.
Carsten Dubs Jens-Peter Ruske Jürgen Krußlich Andreas Tünnermann 《Optical Materials》2009,31(11):1650-1657
The fabrication of epitaxially grown Zn-substituted LiNbO3 (Zn:LiNbO3) waveguide films and rib waveguides is reported and detailed investigations about microstructure, morphology and optical waveguide properties are provided. Zn:LiNbO3 films were grown on congruent X-cut LiNbO3 substrates by a modified liquid phase epitaxy in solid–liquid coexisting solutions. The homogeneously Zn-substituted films exhibit high crystalline perfection and extremely flat surfaces with averaged surface roughness of rms = 0.2–0.3 nm. At the film/substrate interface a Zn-containing transient layer has been observed, which allows the growth of elastically strained Zn:LiNbO3 film lattices. X-ray diffraction reciprocal-space measurements prove the pseudomorphic film growth. The refractive index difference between substrate and film depends on the zinc substitution content, which increase with rising growth temperatures. For films with 5.3 mol% Zn (Δno ≈ +5 × 10−3) only ordinary ray propagation was observed, while for films with 7.5 mol% Zn (Δno ≈ +8 × 10−3, Δne ≈ +5 × 10−3) both modes, TM and TE propagate. Stress-induced refractive index changes are in the order of Δn ≈ 10−4. In rib waveguide microstructures singlemode propagation with nearly symmetrical field distribution has been observed. To demonstrate the potential of the proton exchange-assisted dry-etching technique interferometer microstructures were fabricated. 相似文献
12.
Metal nanoparticles synthesized by sequentially ion-implanted Ag and Cu into silica glasses have been studied. The implantation doses (×1016 ions/cm2) were 5Ag, 5Cu and 5Ag/5Cu, respectively. The optical and microstructural properties of the nanoparticles were characterized by optical absorption spectra and transmission electron microscopy (TEM), respectively. Fast nonlinear optical refraction and nonlinear optical absorption coefficients were measured at 1064 nm of wavelength using Z-scan technique. Results in this paper indicate that the nonlinear refractive index for the Ag/Cu implanted system has a higher value compared to single Ag or Cu implantation nanoparticles. 相似文献
13.
The optical properties of intrinsic SnO2 (TO) and fluorine doped (FTO) are characterized in terms of the dielectric function ε(ħω) = ε1(ħω) + iε2(ħω) by electronic structure calculations. The intrinsic TO shows intriguing absorption characteristics in the 3.0–8.0 eV region: (i) the low energy region of the fundamental band gap (3.2 < ħω < 3.9 eV), the optical transitions Г3+ → Г1+ (valence-band maximum to conduction-band minimum) is symmetry forbidden, and the band-edge absorption is therefore extremely weak. (ii) In the higher energy region (3.9 < ħω < 5.1 eV) the Г5− → Г1+ transitions (from the second uppermost valence band) is strongly polarized perpendicular to the main c axis. (iii) Transitions with polarization axis parallel to c axis are generated from Г2− → Г1+ transitions (from the third uppermost valence bands), and dominates at high energies (5.1 < ħω eV). Heavily F doped TO (FTO) with doping concentrations nF = 4 × 1020 cm− 3 changes the absorption significantly: (iv) Substitutional FO generates strong inter-conduction band absorption at 0.8, 2.2, and 3.8 eV which affects also the high frequency dielectric constant ε∞. (v) Interstitial Fi is inactive as a single dopant, but act as a compensating acceptor in highly n-type FTO. This explains the measured non-linear dependence of the resistivity with respect to F concentration. 相似文献
14.
Yingliang Wei Chen Shao Jinbo Liu 《Materials science & engineering. C, Materials for biological applications》2009,29(8):2442-2447
A sensitive electrochemical method was described for voltammetric determination of ethamsylate at a glassy carbon electrode (GCE) coated with a nano-material thin film. In this work, a nanometer material, namely, multi-wall carbon nanotubes (MWCNT) was dispersed successfully into water in the presence of dihexadecyl hydrogen phosphate (DHP) and a MWCNT–DHP composite film was conveniently obtained on the GCE surface. The electrochemical behavior of ethamsylate at this modified electrode was investigated and a pair of reversible redox peak was observed. Compared with the electrochemical response of ethamsylate at the bare GCE, the separation of peak potential (ΔEp) of ethamsylate decreased obviously from 438 to 40 mV and the current density of redox peaks increased greatly. Based on this, differential pulse voltammetry (DPV) was employed to determine ethamsylate. Various experimental parameters such as pH value of the supporting electrolyte, the amount of modifier and so on were optimized. Under optimal conditions, a linear response of ethamsylate was obtained in the range from 1.0 × 10− 6 to 2.0 × 10− 5 mol/L, and the detection limit was 6.0 × 10− 7 mol/L. The proposed method was successfully applied to detect ethamsylate in pharmaceutical samples. 相似文献
15.
S.I. Kwon S.J. Lee T.H. Jung S.B. Park J.H. Park W.C. Song I.N. Kang D.G. Lim 《Thin solid films》2009,517(23):6298-1164
We investigated the effects of a high density O2 plasma treatment on the structural and electrical properties of sputter-deposited GZO films. The GZO films were deposited on polyimide substrate without substrate heating by RF magnetron sputtering from a ZnO target mixed with 5 wt.% Ga2O3. Prior to the GZO film growth, we treated a polyimide substrate with highly dense inductively coupled oxygen plasma. The optical transmittance of the GZO film, about 80%, was maintained regardless of the plasma pre-treatment. However, the resistivity of the film was strongly influenced by the plasma pre-treatment. The resistivity of the GZO film decreased from 1.02 × 10− 2 Ω cm without an O2 plasma pre-treatment to 1.89 × 10− 3 Ω cm with an O2 plasma pre-treatment. 相似文献
16.
Byung Du Ahn Young Gun Ko Sang Hoon Oh Jean-Ho Song Hyun Jae Kim 《Thin solid films》2009,517(23):6414-1067
The present work was made to investigate the effect of oxygen pressure of SiOx layer on the electrical properties of Ga-doped ZnO (GZO) films deposited on poly-ethylene telephthalate (PET) substrate by utilizing the pulsed-laser deposition at ambient temperature. For this purpose, the SiOx buffer layers were deposited at various oxygen pressures ranging from 13.3 to 46.7 Pa. With increasing oxygen pressure during the deposition of SiOx layer as a buffer, the electrical resistivity of GZO/SiOx/PET films gradually decreased from 7.6 × 10− 3 to 6.8 × 10− 4 Ω·cm, due to the enhanced mobility of GZO films. It was mainly due to the grain size of GZO films related to the roughened surface of the SiOx buffer layers. In addition, the average optical transmittance of GZO/SiOx/PET films in a visible regime was estimated to be ~ 90% comparable to that of GZO deposited onto a glass substrate. 相似文献
17.
Structural, electrochemical and optical comparisons of tungsten oxide coatings derived from tungsten powder-based sols 总被引:2,自引:0,他引:2
Tungsten trioxide (WO3) electrochromic coatings have been formed on indium tin oxide-coated glass substrates by aqueous routes. Coating sols are obtained by dissolving tungsten powder in acetylated (APTA) or plain peroxotungstic acid (PTA) solutions. The structural evolution and electrochromic performance of the coatings as a function of calcination temperature (250 °C and 400 °C) have been reported. Differential scanning calorimetry and X-ray diffraction have shown that amorphous WO3 films are formed after calcination at 250 °C for both processing routes; however, the coatings that calcined at 400 °C were crystalline in both cases. The calcination temperature-dependent crystallinity of the coatings results in differences in optical properties of the coatings. Higher coloration efficiencies can be achieved with amorphous coatings than could be seen in the crystalline coatings. The transmittance values (at 800 nm) in the colored state are 35% and 56% for 250 °C and 400 °C-calcined coatings, respectively. The electrochemical properties are more significantly influenced by the method of sol preparation. The ion storage capacities designating the electrochemical properties are found in the range of 1.62–2.74 × 10− 3 (mC cm− 2) for APTA coatings; and 0.35–1.62 × 10− 3 (mC cm− 2) for PTA coatings. As a result, a correlation between the microstructure and the electrochromic performance has been established. 相似文献
18.
By performing Z-scan method with a femtosecond laser (800 nm, 50 fs, 1 kHz), we investigated the third-order optical nonlinearities of a cuprous oxide (Cu2O) film. Single-phase Cu2O film deposited on a quartz substrate was obtained using the pulsed laser deposition technique. The structure properties, surface morphology and optical transmission spectrum were characterized by X-ray diffraction, scanning electron microscopy and double beam spectrophotometer, respectively. The Z-scan results show that the Cu2O film exhibits large nonlinear refractive index, n2 = 3 × 10− 3 cm2/GW, while the two-photon absorption coefficient, α2 = 40 cm/GW, is relatively small. It implies that the Cu2O film is a promising candidate for nonlinear photonic devices. 相似文献
19.
The structural and superconducting properties of Eu-doped (Bi,Pb)-2212 superconductor have been studied. Eu concentration is varied from x = 0.0 to 0.4 in a general stoichiometry of Bi1.6Pb0.5Sr2−xEuxCa1.1Cu2.1Oy. It is found that the Eu atoms enter into the crystal structure by replacing Sr atoms and induce significant changes in lattice parameters, microstructure, hole-concentration and normal-state conductivity of the system. The critical temperature (TC) and critical current density (JC) at self-field of the Eu-doped samples enhanced considerably for optimum doping levels. Maximum TC-onset of 95.7 K (for x = 0.2) and JC of 1196 A/cm2 at 64 K (for x = 0.1) were observed for doped samples as against 79.8 K and 105 A/cm2, respectively, for the pure sample. The results are discussed on the basis of the changes in hole-concentration due to Eu-doping. 相似文献
20.
Mohammad Kazem Rofouei Moslem Mohammadi Mohammad Bagher Gholivand 《Materials science & engineering. C, Materials for biological applications》2009,29(7):2154-2159
A plasticized poly (vinyl chloride) membrane electrode based on 1,3-bis(2-methoxybenzene)triazene (MBT) for highly selective determination of mercury(II) has been developed. The electrode showed a good Nernstian response (30.2 ± 0.3 mV decade− 1) over a wide concentration range (1.0 × 10− 7−1.0 × 10− 2 mol L− 1). The limit of detection was 5.0 × 10− 8 mol L− 1. The electrode has a response time about 15 s and can be used for at least 1 month without observing any deviation from Nernstain response. The proposed electrode revealed an excellent selectivity toward mercury(II) ion over a wide variety of alkali, alkaline earth, transition, and heavy metal ions and could be used in the pH range 2.6–4.2. The electrode was used in the determination of Hg2+ in aqueous samples and as an indicator electrode in potentiometric titration of Hg(II) ions. 相似文献