Novikov, V. V.Mitroshenkov, N. V.Matovnikov, A. V.Kuznetsov, S. V....
7页查看更多>>摘要：The temperature dependence of the heat capacity C-p(T), (2-300 K), and the lattice parameters a(T), b(T), and c (T) (5-300 K) TmF3 were experimentally studied. Anomalies in the studied characteristics were identified due to the influence on the thermal properties of trifluoride of the crystal field, and at the lowest temperatures (2-10 K), of a possible glass-like contribution due to disorder in the crystal lattice. As a result of our analysis of the excess contribution to the heat capacity (Schottky contribution, C-Sch(T)), we proposed a simplified scheme based on 1-17-5 splitting of the ground state of the Tm3+ ion, and determined the splitting parameters. The influence of the crystal field is also manifested through anomalies in the thermal expansion of TmF3. The temperature dependences of the unit cell volume of thulium trifluoride, and its heat capacity, were analysed using the Debye-Einstein model, and the model parameters are determined.
原文链接:
NSTL
Elsevier
Kumar, AnilKumar, MaheshTanwar, PraveenSharma, Prince...
7页查看更多>>摘要：ABSTR A C T In this article, we report the optical probing of SnTe (275 nm and 33 nm) and Indium-doped SnTe films (50 nm) which are deposited using thermal evaporation. XRD (X-ray diffraction) and Raman spectroscopy are used to characterize the films. Additionally, the optical characteristics of the material are examined using reflectance and PL (photoluminescence) spectroscopy. Simultaneously, the dynamics of charge carriers are studied using TRUS (Transient reflectance ultrafast spectroscopy). The TRUS probes the thin films in the visible to near-infrared range (400-1600 nm) with a probe latency of a few femtoseconds to 6 ns. The study demonstrates the pres-ence of a resonant state in SnTe, which becomes more prominent and metastable with indium doping.
原文链接:- NSTL
- Elsevier
Hoang, Thu TrangPham, Thanh SonNguyen, Xuan BachNguyen, Huu Tu...
7页查看更多>>摘要：We report a numerical study of metal-dielectric-metal (MDM) plasmonic metasurface-based refractive index sensors that have high contrast and sensitivity in the near-infrared region. The MDM plasmonic metasurface is formed by stacking up silver (Ag) subwavelength disk array on thin silica (SiO2) spacer-layer and Ag film (acting as a reflector) on a silicon substrate. The MDM plasmonic metasurfaces with various heights, Ag disk diameters and SiO2 spacer-layer thicknesses are designated and numerically investigated using a finite-difference time-domain method. As results have shown, the optical properties of the device are weakly dependent on the height of Ag disks, but strongly dependent on the size of Ag disks and SiO2 spacer-layer thickness. By looking at the field distribution at the resonance, the strong confinement of incident light localized inside the SiO2 spacer-layer, thus extremely low reflection closed to 0%, corresponding to the absorption of up to 100% and high quality-factor (Q- factor) of similar to 180 have been achieved. Because of operating in the near-infrared range, the proposed MDM plas-monic metasurface has low Ohmic loss, and then the refractive index biosensor based on that shows the figure-of-merit (FOM) to have the contrast and selectivity higher than that of other established MDM plasmonic bio-sensors. The sensitivities of 1109 nm/RIU and 1290 nm/RIU according to FOMs of 38.8 and 95.3, which correspond to the vapor and liquid sensors, respectively, have been achieved. Our systematic investigation provides useful guidelines for designing MDM plasmonic metasurface sensing devices.
原文链接:- NSTL
- Elsevier
Mamdouh, SamarMahmoud, AlaaSamir, AhmedMobarak, Mohamed...
9页查看更多>>摘要：The nonlinear optical properties of silver nanoparticles (AgNPs) colloids in distilled water, when irradiated with 100 fs laser pulses, were investigated experimentally using the Z-scan technique. At a constant wavelength of 760 nm and different excitation powers, the nonlinear absorption coefficient and nonlinear refractive index were measured. The AgNPs colloids are synthesized by laser ablation of silver bulk in distilled water using a 532 nm Nd: YAG laser with different ablation energies fluence of 9, 15.5, and 26x10(4) (J/cm(2)) over a 30min ablation time. The nanoparticle size, shape, and absorption spectra of nanoparticle colloids were determined using transmission electron microscopy and an ultraviolet-visible spectrophotometer. Spherical AgNPs are formed with an average diameter ranging from 7.5 to 12 nm. As the laser ablation energy fluence increases, the average size of the AgNPs decreases while the bandgap energy increases. As the excitation laser power and AgNPs size increase, the nonlinear absorption coefficient and nonlinear refractive index decrease. The optical limiting performance of AgNPs improves with increasing laser ablation energy fluence, with the best performance at 26x10(4) (J/cm(2)).
原文链接:- NSTL
- Elsevier
Dana, Bereket DalgaKoya, Alemayehu NanaSong, XiaoweiLin, Jingquan...
9页查看更多>>摘要：Fano resonance (FR) owns a sharp asymmetric line shape, low radiation loss and huge modification ability so that enhancing Fano resonance in asymmetric dimers is a topic of interest in nanophotonics and plasmonics, which has potentials in sensing applications. Here, we theoretically investigated the enhancement and tunability of Fano resonance in shape-asymmetric gold nanoring-nanodisk dimer through varying the size of nanodisk (ND) and polarization angle (theta). The intensity of this mode was significantly enhanced by changing the aforementioned parameters. Furthermore, we studied the performance of FR in terms of the quality factor (Q(F)) and figure of merit (FoM). It is found that the Q(F) (FoM) of this mode decreases (increases) exponentially (linearly) with increasing ND and theta. We explored the sensitivities of FR with maximum FoM to assess the capability of this mode in the detection of refractive index. Moreover, our design displays enhanced performance by increasing the size of ND and the polarization angle of the incident light offering another degree of freedom for exploring and modulating asymmetric dimers. This approach provides insights into the enhanced and tunable FR with remarkable potential in sensing and switching applications.
原文链接:- NSTL
- Elsevier
Khurana, KanikaRani, NirmalaJaggi, Neena
10页查看更多>>摘要：Multi-metallic nanoparticles (NPs) offer tunable Localized Surface Plasmon Resonance properties which depend on their elemental and configurational variations, which have been used in optical sensing and biomedical imaging. In the present study, the composition and optical properties of hybrid nano-structured thin films of CdS quantum dots (QDs) incorporated on Au-, Ag- and Cu-NPs for photonic applications are investigated. Initially, CdS QDs were prepared by chemical reduction method and characterized by Transmission electron microscopy, UV-Visible absorption spectroscopy and Fourier transform infrared spectroscopy techniques. Then nanometer thin films of Au, Ag and Cu were fabricated by thermal evaporator and insitu heating along with uniform rotation of substrate was used to convert these into respective uniform spherical NPs on ITO substrate. Further, CdS QDs were deposited over these metallic NPs and we observed enhanced photoluminescence (PL) of CdS QDs due to Surface Plasmon Resonance effect by these metallic NPs. The time resolved spectroscopy of these films was carried out to correlate the enhanced PL emission from CdS-Au-Ag-Cu-ITO thin film. The results of the present study of these plasmonic nanostructures will be further utilized in metal enhanced fluorescence sensors.
原文链接:- NSTL
- Elsevier
Chauhan, SantoshJaiswal, Shivendra Kumar
9页查看更多>>摘要：Doped perovskite-type oxides have diversified applications in sensors, inorganic membranes, piezoelectricity, and solid oxide fuel cells. An attempt has been made here to synthesize (Ba0.5Sr0.5)(Fe1-xCex)O3-delta (x = 0 - 1.0) powders by decomposition of sol-gel derived oxalate at 750-950 ?degrees C for 5 h to study the effect of cerium insertion with regard to Fourier transform infrared (FTIR) bands and magnetic characteristics. It is shown that the coercivity (H-c) increases from similar to 83.4 to 1985 Oe and saturation magnetization decreases from similar to 0.146 to 0.041 emu/g as structure changes from cubic (x = 0) to orthorhombic (x = 1.0). The law of saturation approximation (LAS) agrees well with observed saturation magnetization. The transition temperatures are found to be similar to 500, 370, and 370.12 K for x = 0, 0.6, and 1.0, respectively. High coercivity (similar to 1985 Oe) and hysteresis in (Ba0.5Sr0.5) CeO3-delta (x = 1.0) arise due to the presence of oxygen vacancies and structural distortion. FTIR spectra show different types of bands related to the iron and/or cerium-oxygen (i.e., Fe/Ce - O) stretching vibrations. The redshift has been observed with cerium in (Ba0.5Sr0.5)(Fe1-xCex)O3-delta. These properties make them useful in magnetic recording and storage applications.
原文链接:- NSTL
- Elsevier
Roustaei, M.Servatkhah, M.
5页查看更多>>摘要：In magnetic hyperthermia (MH), malignant cells are destroyed by heating the tumor tissue. The magnetic nanoparticles (MNs) are injected to tumor region and an alternating magnetic field is exerted to the region. The temperature distribution relates to the MNs distribution inside the tumor. Here, we consider that a spherical tumor tissue is embedded in a normal tissue. We employ a theoretical model to study the distribution of temperature within a tumor with considering injection of MNs inside the tumor. For this goal, the mass transfer and diffusion theories in interstitial tissue are used with Rosensweig's and Pennes equations. We have first obtained analytically.the interstitial pressure and interstitial transfer of MNs by diffusion equation. We have also obtained analytically the concentration distribution inside the tumor. Finally, temperature distribution is obtained numerically. From the obtained results, it is found that the temperature distribution depends on particle size, injection concentration and injection dose. Since the spherical tumor is considered in this work, the injection of magnetic fluid is selected in the radial direction. It is found that the best results for hyperthermia can be obtained with considering the intermediate radius of MNs, high injection dose and concentrations.
原文链接:- NSTL
- Elsevier
Zargar, Rayees AhmadKumar, KundanMohmoud, Zakaria M. M.Shkir, Mohd...
6页查看更多>>摘要：Designing of appropriate thin film is important for controlling the absorbance, reflection and transmission of specific wavelength of electromagnetic radiation and which will ultimately enhance the optoelectronic properties. This paper presents optical analysis of ZnO thin films using transmission spectra derived by Sellmeier model upon different thickness. For that a famous computing language "MATLAB" was employed to generate transmission data. The transmittance profile of ZnO/glass films was examined for diverse thicknesses (600 nm, 700 nm, 800 nm). Further, the different parameters such as index of refraction, coefficient of extinction, band gap and constant of dielectric were calculated by different formulas with respect to wavelength in the UV-visible region under different thickness. It is also found that the thickness-based interference on transmission and reflectance characteristics were altered by film thickness. This sort of research work will help us to find out the suitable thin film thickness coating for designing micro/nano optoelectronic devices.
原文链接:- NSTL
- Elsevier
Patra, BivasGhosh, BinitaBanerjee, SourishSinha, T. P....
7页查看更多>>摘要：The Optical and dielectric mechanism of complex double perovskite oxides xLaAlO3 - (1-x)Ba(Mg1/2W1/2)O3 [LA-BMW] have been characterized for different values of x (0.10, 0.25, 0.50, 0.75 and 0.90). UV-Visible absorption optical spectra show that with increase in concentration x, the band gap of the corresponding sample slowly decreases from 5.59eV to 4.75eV systematically. The dielectric data have been measured using a LCR meter (Hioki-3532-50, Japan) in the frequency range from 50 Hz to 4.8 MHz as a function of temperature varying from 300 K to 723 K. The dielectric data shows that room temperature conductivity increases with increase in the doping concentration x. A comparative study has been carried out to corelate structural variation with change in band gap which in turn effects the electrical properties of the samples.
原文链接:- NSTL
- Elsevier
