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1.
Optical emission spectra of the plasma produced by 1.06 μm Nd:YAG laser ablation of SnO2:Sb transparent conducting thin film were recorded and analyzed as functions of distance from the target surface and incident laser power density in air and in vacuum. Ambient gas effects on pulsed laser ablation of target were analyzed in detail. We also discussed how the air takes part in the plasma evolution process and confirmed that the ignition of the air plasma is by the collisions between the energetic electrons and the nitrogen atoms through a cascade avalanche process.  相似文献   

2.
The use of amorphous chalcogenides offers advantages such as remarkable optical properties like a wide transmission window (∼1-20 μm) depending upon composition, making them suitable for sensitive detection of clinical or environmental changes. They also present interesting high (non)linear refractive indices, photorefractive effects, and other properties interesting for wavelength conversion, all-optical switching or modulation, Raman and parametric amplification, laser sources for mid-IR, etc.Slab waveguides based on chalcogenide amorphous films with good adherence and controlled composition can be obtained using pulsed laser deposition allowing to design and to manufacture complex optical functions on waveguides within a small and compact chip. The aim of this work is to characterize the ejection plume obtained by laser ablation of AsxSe100−x samples in order to get some insight on the process involved for optimizing the pulsed laser deposition process. The dynamics of the plume has been systematically investigated by ICCD camera fast imaging and space- and time-resolved optical emission spectroscopy for samples of various compositions.  相似文献   

3.
纳米晶SnO2透明导电薄膜的研制   总被引:3,自引:1,他引:2  
阐述了金属氧化物透明导电薄膜研究的发展情况及其应用前景。介绍了采用磁控溅射技术,使用混合气体Ar和O  相似文献   

4.
Tin dioxide (SnO2) nanoparticles having 3 nm size were synthesized by irradiating pure tin metal using high power Nd:YAG laser in deionized water. Formation of nano-SnO2 crystallites was confirmed by X-ray diffraction (XRD) and AFM study. UV-vis absorption spectral studies showed a peak at 240 nm. FTIR spectrum showed a band in the range of 400-700 cm−1 which was assigned to Sn-O antisymmetric vibrations. Photoluminescence spectrum of synthesized SnO2 nanoparticles showed peak corresponding to 3.175, 2.901 and 2.613 eV respectively.  相似文献   

5.
The antimony doped tin oxide (SnO2:Sb) (ATO) thin films were prepared by oblique angle electron beam evaporation technique. X-ray diffraction, field emission scanning electron microscopy, UV-vis-NIR spectrophotometer and four-point probe resistor were employed to characterize the structure, morphology, optical and electrical properties. The results show that oblique angle deposition ATO thin films with tilted columns structure are anisotropic. The in-plane birefringence of optical anisotropy is up to 0.035 at α = 70°, which means that it is suitable as wave plate and polarizer. The electrical anisotropy of sheet resistance shows that the sheet resistance parallel to the deposition plane is larger than that perpendicular to the deposition plane and it can be changed from 900 Ω/□ to 3500 Ω/□ for deposition angle from 40° to 85°, which means that the sheet resistance can be effectively tuned by changing the deposition angle. Additionally, the sandwich structure of SiO2 buffer layer plus normal ATO films and oblique angle deposition ATO films can reduce the resistance, which can balance the optical and electrical anisotropy. It is suggested that oblique angle deposition ATO thin films can be used as transparent conductive thin films in solar cell, anti-foggy windows and multifunctional carrier in liquid crystal display.  相似文献   

6.
Zinc peroxide nanoparticles having grain size less than 5 nm were synthesized using pulsed laser ablation in aqueous solution in the presence of different surfactants and solid zinc target in 3% H2O2. The effect of surfactants on the optical and structure of ZnO2 was studied by applying different spectroscopic techniques. Structural properties and grain size of the synthesized nanoparticles were studied using XRD method. The presence of the cubic phase of zinc peroxide in all samples was confirmed with XRD, and the grain sizes were 4.7, 3.7, 3.3 and 2.8 nm in pure H2O2, and H2O2 mixed with SDS, CTAB and OGM respectively. For optical characterization, FTIR transmittance spectra of ZnO2 nanoparticles prepared with and without surfactants show a characteristic ZnO2 absorption at 435-445 cm−1. FTIR spectrum revealed that the adsorbed surfactants on zinc peroxide disappeared in case of CTAB and OGM while it appears in case of SDS. This could be due to high critical micelles SDS concentration comparing with others which is attributed to the adsorption anionic nature of this surfactant. Both FTIR and UV-vis spectra show a red shift in the presence of SDS and blue shift in the presence of CTAB and OGM. The blue shift in the absorption edge indicates the quantum confinement property of nanoparticles. The zinc peroxide nanoparticles prepared in additives-free media was also characterized by Raman spectra which show the characteristic peaks at 830-840 and 420-440 cm−1.  相似文献   

7.
Dense SnO2 nanocondensates with fluorite-type-related structures have been synthesized via severe heating-cooling under energetic Nd-YAG laser pulse irradiation of the Sn target in oxygen ambient. Transmission electron microscopic observations indicated that the fluorite type transformed in a martensitic manner into a baddeleyite-type structure with accompanied dislocations, twinning, commensurate shearing and shape change. The Pa3¯-modified fluorite-type structure was hardly observed possibly due to its transformation into α-PbO2 type and then rutile-type structures in the dynamic process.  相似文献   

8.
We have successfully prepared a novel nanoparticle solution of Sr2MgSi2O7: Eu2+, Dy3+ with afterglow properties by means of laser ablation in liquid. This process also produced by-products of different kinds, depending on the liquid used. The amount of by-product and the size of the nanoparticles were controlled by the energy density of laser ablation. The amount of by-product was reduced by a decrease in the energy density, which also decreased the particle size of the nanoparticles. The PL spectrum of the nanoparticles was the same as that of the target materials used for laser ablation. The afterglow properties deteriorated with a decrease in particle size. We concluded that an increase in specific surface area caused by a decrease in particle size resulted in the decrease of luminescent intensity.  相似文献   

9.
In this work, the continuum spectrum of X-rays originated from the interaction of a moderate intensity ns Nd:YAG laser (1064 nm, 9 ns, 30 Hz, 900 mJ, 1011 W/cm2) with Ta target producing plasma is investigated. Plasma expands unisotropically with a velocity, depending on the pressure of the residual gas in the vacuum chamber. The X-ray intensity is a function of the laser energy and of the gas pressure inside the chamber. The X-ray energy is measured with an X-ray filter positioned in front of the Si(Li) solid-state detector. A temperature of about ~1–2 keV of the hot electrons, responsible for the continuum spectrum emission from the plasma, is calculated from the fit of the X-ray spectrum, applying a Maxwellian distribution.  相似文献   

10.
A Pr3+-doped KY(MoO4)2 single crystal was grown by the Czochralski method. The polarized absorption and fluorescence spectra of the Pr3+:KY(MoO4)2 crystal were measured at room temperature. The stimulated emission cross-sections for the transitions from the 3P0 multiplet were estimated from the fluorescence spectra. The fluorescence lifetime of the 3P0 multiplet was estimated from the fluorescence decay curve at room temperature. The analysis of spectral properties shows that the Pr3+:KY(MoO4)2 crystal is a promising gain medium for visible lasers.  相似文献   

11.
Impedance studies of Sb doped SnO2 thin film prepared by sol gel process   总被引:1,自引:0,他引:1  
Antimony-doped tin oxide thin films have a range of technological applications as conductive coatings, and sol-gel processing seems to offer some advantages over other coating techniques. In this study antimony-doped tin oxide (ATO) thin films have been prepared by the sol-gel dip-coating (SGDC) process, using tin (II) chloride dehydrate (SnCl2, 2H2O) and antimony (III) chloride (SbCl3) as host and dopant precursors respectively. The structure of the (ATO) powders was analysed by X-ray diffraction (XRD) and the microstructure of the thin films by atomic force microscopy (AFM). These investigations show that the structure is tetragonal rutile type and that an increase in Sb-doping decreases the crystallite size of the (ATO) particles. To analyze the impedance spectroscopy data, the Nyquist (Z″ vs. Z′) plots as well as the representation of imaginary (Z″) and real (Z′) parts of impedance vs. frequency were used. The Nyquist plots suggest that only the grain boundaries are responsible in the conduction mechanism of the material. From the variation of lnσ vs. inverse of absolute T we have deduced the activation energy found to be 0.87 eV.  相似文献   

12.
The ablation process of La0.5Sr0.5CoO3 by a spatial uniform 248 nm excimer laser beam has been characterized. Ablation rates, changes in the target surface morphology and composition have been studied as a function of the laser fluence. The dependence of the ablation rate on the laser fluence has been explained by a model based on plasma absorption. The threshold fluence for complete dissociation of the surface has been determined and is found equal to 0.7 J/cm2. Above this threshold, a steady-state target surface condition is obtained within 30 pulses. Below the threshold fluence, CoO nuclei form, which have a pronounced effect on the target composition and morphology. In addition, ellipsometric and reflectance spectra have been measured in the photon energy range of 1.8 to 5.0 eV.  相似文献   

13.
We report on the design and fabrication of complex microcomponents based on multimode optical interference, using a CO2 laser ablation technique. Mode confinement, power division and losses are assessed. Power splitters show a good balance in the intensity division but beam combiners exhibit a variation in output power. The devices are compact and show a low sensitivity to imperfections in the fabrication process. The results demonstrate the technique's potential to develop multiport integrated circuits.  相似文献   

14.
研究了Yb:KLu(WO4)2晶体对非偏振抽运光的吸收以及连续波激光振荡性质. 晶体结构的低对称性导致晶体光谱呈强烈各向异性,最强的吸收和发射都发生在平行于Nm主轴的偏振方向上. Ng切向晶体具有最高的非偏振抽运光吸收效率和最大的激光功率产生潜力,2 mm长的晶体产生的最高连续波输出功率为11 W,相对于吸收抽运功率,光—光转换效率为68%,而斜率效率则达80%. 关键词: 吸收谱 发射谱 激光振荡 各向异性  相似文献   

15.
Er3+:SrMoO4 crystal of high optical quality was grown by the Czochralski method. The room temperature polarized absorption and emission spectra together with the lifetime decay curve were measured. Based on the Judd-Ofelt theory, three intensity parameters, radiative transition rates, radiative lifetimes and fluorescent branching ratios, were obtained. Emission cross-section and gain cross-section around 1.54 μm were also obtained.  相似文献   

16.
Titanium dioxide nanoparticles in distilled H2O solvent were prepared by laser ablation. The experiments were performed irradiating a Ti target with a second harmonic (532 nm) output of a Nd:YAG laser varying the operative fluence between 1 and 10 J cm−2 and for an ablation time ranging from 10 to 30 min. Electron microscopy measurements have evidenced the predominant presence of nanoparticles with diameter smaller than 10 nm together with agglomerations of 100-200 nm whose content increases with the laser fluence. At low laser fluence the particles’ size distribution shows that more than 85% of the nanoparticles have a size smaller than 5 nm while at mid and high fluences the presence of 5-7 nm nanoparticles is predominant. XPS analysis has revealed the presence of different titanium suboxide phases with the prevalence of Ti-O bonds from TiO2 species. The optical bandgap values, determined by UV-vis absorption measurements, are compatible with the anatase phase.  相似文献   

17.
X-ray photoelectron core-level and valence-band spectra for pristine and Ar+-ion irradiated (0 0 1) surfaces of AgCd2GaS4 and AgCd2GaSe4 single crystals grown, respectively, by the Bridgman method and the method of direct crystallization have been measured in the present work. The X-ray photoelectron spectroscopy (XPS) results reveal high chemical stability of (0 0 1) surfaces of AgCd2GaS4 and AgCd2GaSe4 single crystals. Electronic structure of AgCd2GaS4 has been calculated employing the full potential linearized augmented plane wave method. For the AgCd2GaS4 compound, the X-ray emission bands representing the energy distribution of the valence Ag d-, Cd d-, Ga p- and S p-like states were recorded and compared on a common energy scale with the XPS valence-band spectrum. The theoretical and experimental data regarding the occupation of the valence band of AgCd2GaS4 were found to be in excellent agreement to each other. Second harmonic generation (SHG) efficiency of AgCd2GaS4 by using the 320 ns CO laser at 5.5 μm has been recorded within the temperature range 80–300 K. Substantial increase of the photoinduced SHG which in turn is substantially dependent on the temperature has been detected for the AgCd2GaS4 compound.  相似文献   

18.
Nd:Ca4YO(BO3)3 (Nd:YCOB) crystal was grown by the Czochralski method, and its structure was measured by using a four circle X-ray diffractometer. The transparent spectrum from 200 to 2600 nm was measured at room temperature. The fluorescence spectrum near 1.06 μm showed that the main emission wavelength of Nd:YCOB crystal was centered at 1060.8 nm. Laser output at 1.06 μm has been demonstrated when it was pumped by a Ti:sapphire laser at the wavelength of 794 nm, the highest output power was 68 mW under pumping power of 311 mW, the pumping threshold was 163 mW and slope efficiency was 46.9%. The self-frequency doubled green light has been observed when it was pumped by a Ti:sapphire or a laser diode (LD). A 14.5 mm Nd:YCOB crystal sample cut at (θ, φ)=(90°, 33°) was used for type I second-frequency generation (SHG) of the 1.06 μm laser pulse. The SHG conversion efficiency was 22%.  相似文献   

19.
The Dy3+-doped NaY(MoO4)2 single crystals were grown successfully by the Czochralski technique. The main spectroscopic properties (absorption, luminescence, decay curve) of Dy3+-doped NaY(MoO4)2 have been determined for both the σ and π polarizations. By using the Judd-Ofelt theory, the measured room temperature absorption spectra were applied to determine the intensity parameters, spontaneous transition probabilities, branching ratios, and radiative lifetimes of Dy3+ transitions. The results show that the Dy3+-doped NaY(MoO4)2 crystal may realize the yellow laser operation.  相似文献   

20.
An easy method of tuning the response of maximum magnetoimpedance (MI) ratio in Fe75.5Si13.5B7Nb3Cu1 amorphous ribbons was investigated by laser ablation. In order to obtain different GMI peak positions, the stripes were ablated by laser with different separations on the surface layer of the ribbon. When the stripes were parallel (or perpendicular) to the applied magnetic field, the peak location of maximum MI ratio would drift to larger (or smaller) external field. And the shift was correlated with the spaces between stripes. The applied fields corresponding to the minimum and maximum values of peak location are 13 Oe and 49 Oe at the frequency of 15 MHz, respectively. The phenomenon can be explained by the anisotropy field induced by demagnetizing field after the laser ablation.  相似文献   

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