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Accurate Number Densities of Ideal Photons in a One-Dimensional Barrel Cavity
摘要： Our experimental scheme is based on a barrel optical microcavity filled with a dye solution. It is found that the number of non-condensed photons is characterized by an analytical function, which involves a q-digamma function in mathematics. We employ the q-digamma function to calculate the spatial and momentum distributions of ideal photons in a one-dimensional barrel cavity. The first main finding in this paper is that the spatial and momentum distributions possess a similar profile. The second main finding is that when photons are in the normal state, the density profile exhibits Friedel oscillations. The third main finding is that when photons are in the BEC state, the density profile exhibits a sharp peak with extremely narrow width. The fourth main finding is that the central peak of the density distribution is a monotonically increasing function of the photon number N but is a monotonically decreasing function of the temperature T.
关键词： Bose-Einstein condensation,One-dimensional photons,Number densities of photons,Optical microcavity
更新于2025-09-23 15:23:52
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Optical measurements based on practical methods for detecting time-wise morphing structures
摘要： Nowadays non-contact measurement methods have become widely used systems in several fields especially robotics, aerospace, architecture, and cultural heritage. Practical devices, taken from mass markets, are increasingly being used in scientific and engineering research fields thanks to their ability to combine good accuracy with to the low-cost and ready-to-use experimental setup. In the present paper, digital image analysis (based on digital camera devices) and three-dimensional scanning technique (based on Kinect I and Kinect II sensors) are compared to evaluate their performance in detecting a time-wise shape modification. Digital camera and Kinect sensors are used to the non-contact detection of a morphing blade able to modify its geometry according to airflow temperature variation. The comparison showed the capability of the digital image technique to provide quantitative information when a proper alignment is adopted, while the three-dimensional scanning process allows the continuous blade detection useful to quantify the shape modification. Two-dimensional and three-dimensional blade shape reconstruction processes are also discussed.
关键词： Reverse Engineering,Non-contact measurement,Point cloud,Kinect sensor,Optical method,Digital image analysis
更新于2025-09-23 15:23:52
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Flat gain C?+?L band using optical amplifiers for 200?×?14?Gbps DWDM system
摘要： This paper has shown the analysis of 200 channels dense wavelength division multiplexing (DWDM) system with the data rate of 14 Gbps for attaining the flat gain for the channel spectrum from 1520 to 1640 nm. Analysis has also extended with the power amplification of erbium–ytterbium co-doped optical amplifier (EYBCDOWA) and Raman optical amplifier for the transmission distance of 120 km to mitigate the effect of crosstalk and bit error rate (BER). Final analysis has also recommended that this proposed system is capable to deliver the flat gain of 19.5 dB with minor variation of 0.95 dB to maintain the acceptable dense communication for long distance.
关键词： Raman optical amplifier,Crosstalk,EYBCDOWA,BER,Flat gain,DWDM
更新于2025-09-23 15:23:52
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Graphdiyne: A promising nonlinear optical material modulated by tetrahedral alkali-metal nitrides
摘要： A new series of the functionalized graphdiyne (GDY) material was designed by adsorbing the tetrahedral Li3NM molecules on the largely delocalized π-conjugated GDY surface, namely Li3NM@GDY (M = Li, Na, K), and its structure, chemical stability, electronic property, and the first hyperpolarizability were investigated by using the density functional theory computations. Our results reveal that the Li3NM molecules can interact with three triangular holes on the GDY surface, in which the van der Waals interactions play a crucial role in enhancing the structural stability. Meanwhile, the total NPA charges on the Li3NM molecules are gradually increased from Li to K, and the Li3NM molecules can transfer an electron to GDY, forming intramolecular electron donor and acceptor pairs. All of studied complexes exhibit the giant static first hyperpolarizabilities (βtot), up to ~2.88 × 105 a.u. for Li3NK@GDY, which can be explained by two-level expression from the TDDFT calculations. This study will inevitably stimulate further synthesis of the novel graphdiyne-based nonlinear optical materials.
关键词： Graphdiyne,Electronic structure,TDDFT,Charge transfer,Nonlinear optical property
更新于2025-09-23 15:23:52
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Dispersion flattened extremely high-birefringent kagome lattice elliptic core photonic crystal fiber in THz regime
摘要： A highly birefringent elliptic porous-core photonic crystal fiber with kagome lattice cladding has been presented for terahertz (THz) wave transmission. The slotted airholes inside the elliptic core effectively disrupt the symmetry of the porous-core which offers extremely high modal birefringence whereas the kagome cladding structure results in significantly low effective material loss (EML). The birefringence of the proposed structure is 9.73 × 10?2 for y-polarized mode at an operating frequency of 1 THz. The suggested structure also provides very flat dispersion over a bandwidth of 300 GHz. It is highly expected that this elliptic core waveguide would be remarkably useful in numerous polarization maintaining THz applications.
关键词： Photonic crystal fibers,Microstructured fibers,Fibres, polarization-maintaining,Optical communications,Fiber design and fabrication
更新于2025-09-23 15:23:52
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Optical-property coefficient estimation of bulky medium in experiments with a succinctly analytical calculation
摘要： Diffuse optical imaging enables to reconstruct distribution of optical properties, absorption and scattering coefficients, in tissue for breast cancer detection based on diffusion equation with the help of the initial guess obtained from measured data. To estimate the initial guess of the optical-property coefficients, an analytical solution of diffusion equation can be used and compared with the measured data. The analytical solution for a homogeneous infinite medium can be obtained in the frequency domain, expressing that the photon intensity and the phase lag relative to the distance between source and detector in a linear relationship. In this study, a succinct calculation using the trigonometric relation is proposed to estimate the optical-property coefficients. A tank-type and a cylinder Lipovenoes phantoms with two concentrations of 1.25% and 2.5% are employed and measured for verification. It is found that the method proposed here shows better results and results in estimation errors of 0–14.81% for μa and 20–42% for μs′.
关键词： Diffusion equation,Photo-density wave experiment,Optical-property coefficients
更新于2025-09-23 15:23:52
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Fraction of Rare-Earth (Sm/Nd)-Lanthanum Ferrite-Based Perovskite Ferroelectric and Magnetic Nanopowders
摘要： Multiferroic compound, especially LaFeO3-based perovskite nanopowders that exhibit robust simultaneous ferromagnetism and ferroelectricity, are widely investigated and applied in different applications. In this work, we report the synthesis and characterization pertaining to fraction of rare-earth (Sm/Nd)-substituted lanthanum ferrite based perovskite nanopowders via solid-state technique. The multiferroic phenomenon is the fundamental approach to combine both the ferromagnetic and ferroelectric properties in a single system. Reduction in crystallite size, as well as some lattice distortion effects, are included to show the possibilities of tuning the lattice structure, electrical, optical as well as the magnetic properties which are closely connected to the ferroelectric behavior and magnetism. At room temperature, the ferroelectric behavior of La0.9(Sm/Nd)0.1FeO3 exhibiting a P-E hysteresis loop became more and more pronounced, indicating the electrical leakage is greatly reduced. The canted antiferromagnetic hysteresis loop shows that the rare-earth (Sm/Nd) ion can significantly affect the magnetic parameters of the materials.
关键词： Lanthanum ferrite,x-ray diffraction,optical and magnetic properties,solid-state reaction,ferroelectric,UV–Vis spectroscopy
更新于2025-09-23 15:23:52
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Spherical LiZnBO3: Structural, Optical and Electrochemical Properties
摘要： Spherical – LiZnBO3 material is synthesized by sol-gel technique and the structural, optical, and electrochemical properties of LiZnBO3 are analyzed. X-ray diffraction result reveals the formation of α-LiZnBO3. Scanning electron microscope and transmission electron microscope image shows spherical morphology and the size of particle is approximetly 80 nm. Absorbance spectra reveal the characteristics band edge of LiZnBO3 is noticed around 210 nm and the band gap is found to be 5.57 eV. Defect-induced intrinsic luminescence is observed in the LiZnBO3 material. The calculated electrical conductivity of LiZnBO3 is 9.52 x 10-9 S/cm. Charge–discharge measurement indicates that the sol-gel synthesized LiZnBO3 delivers a first charge-capacity of 78.82 mAh g-1 at C/10 rate and yields the discharge capacity of 7 mAh g-1 at the 10th cycle. An improved capacity is expected to be reached by further reduction in particle size, doping and conductive carbon coating.
关键词： Sol-gel,Spherical,Optical and electrochemical properties,LiZnBO3
更新于2025-09-23 15:23:52
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Fascinating Physical Properties of 2D Hybrid Perovskite [(NH3)(CH2)7(NH3)]CuClxBr4?x, x?=?0, 2 and 4
摘要： The 2-D organic–inorganic hybrid perovskites of the formula [(NH3)(CH2)7(NH3)]CuClxBr4?x, x = 0, 2 and 4 were prepared by slow evaporation from ethanolic solution in stoichiometric ratio 1:1 (organic/inorganic). Microchemical analysis and x-ray diffraction (XRD) were used to confirm the formation of the presently investigated hybrids. Differential scanning calorimetry (DSC) indicated order–disorder transitions at T1 = 357 K, T2 = 388 K, and T3 = 398 K for x = 0, 2 and 4 of the three heptane diammonium Cu hybrid perovskites, respectively. These transitions are in good agreement with the electrical permittivity results at different frequencies and temperatures. Optical properties and estimated band gap energy reveal that the band gap energy decreases sharply with replacement of Cl ion by Br ion where the band gap energy of [(NH3)(CH2)7(NH3)]CuBr4, x = 0 (denoted 2C7CuBr) is 1.6 eV (brown color) and for [(NH3)(CH2)7(NH3)]CuCl4, x = 4 (denoted 2C7CuCl) is 2.6 eV (yellow color). The differential magnetic susceptibility of 2C7CuBr in the temperature range 80–300 K indicates the effective magnetic moment μeff = 2.05 BM.
关键词： 2D hybrid perovskite,optical properties of halide perovskite,phase transition,magnetic properties of Cu perovskite
更新于2025-09-23 15:23:52
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Effect of Nd doping on structural and opto-electronic properties of CdO thin films fabricated by a perfume atomizer spray method
摘要： A perfume atomizer-assisted spray pyrolysis method was employed to fabricate undoped and neodymium (Nd)-doped cadmium oxide (CdO) thin films. X-ray diffraction results reveal that all the films are polycrystalline with a cubic structure with a preferential orientation along the (200) direction. Scherrer’s formula was used to calculate the crystallite size of Nd-doped CdO films. Energy dispersive spectroscopy results show that Cd, Nd and O elements are present in Nd-doped CdO thin films. The optical absorption of the doped films is increased along with increasing Nd-doping level. The prepared CdO thin films have a high absorption coefficient in the visible region and the optical band gap is decreased on increasing Nd doping content. The electrical carrier concentration (n) of the deposited films is increased with increasing Nd doping concentration. Photoconductivity studies of a nanostructured Al/Nd–n-CdO/p-Si/Al device showed a non-linear electric characteristics indicating diode-like behaviour. Prepared Nd:CdO films could increase the photo-sensing effect of this n-CdO/p-Si heterostructure. These Nd-doped CdO thin films may open a new avenue for photodiode application in near future.
关键词： optical and electrical properties,Nd:CdO,thin films,spray using perfume atomizer
更新于2025-09-23 15:23:52