Optical and Quantum Electronics最新文献

The analytical propagation functions for partially coherent vortex cosine-hyperbolic-Gaussian beams (PCvChGB) propagating through uniaxial crystal orthogonal to the optical axis are derived, and numerical examples analyze their spreading properties. It's shown that the intensity distribution of the PCvChGB is astigmatic and related to the initial beam parameters, namely the decentered parameter b and topological charge M, the coherence length (sigma_{0}), and the ratio of refractive index ({{n_{e} } mathord{left/ {vphantom {{n_{e} } {n_{0} }}} right. kern-0pt} {n_{0} }}). The obtained results could be beneficial for application of partially coherent beam in anisotropic medium.

This study focuses on the fabrication of WO₂I₂/poly o-amino-thiophenol porous spherical-nanocomposite (WO₂I₂/POATP PS-nanocomposite) with promising optical absorbance for photodetector applications. The PS-nanocomposite is synthesized through the oxidation of o-amino-thiophenol using iodine, followed by a reaction with Na₂WO₄. The resulting nanocomposite exhibits wide optical absorbance extending into the IR region and a small bandgap of 2.0 eV. The spherical particles have pores with a diameter of 5 nm, and their crystalline peaks demonstrate excellent crystallinity with a crystal size of 121 nm. This combination of crystalline behavior, morphology, and optical absorbance suggests that the WO₂I₂/POATP PS-nanocomposite is a highly sensitive photodetector suitable for a broad optical spectrum, including UV, visible, and IR regions. The device’s application in photon sensing is evaluated by measuring the photocurrent using linear sweep voltammetry, determining the current density (Jph) under light and dark conditions (Jo). The Jph and Jo values are found to be 0.8 and 0.48 mA/cm², respectively, resulting in a photocurrent of 0.32 mA/cm², a promising value that indicates significant photon sensitivity. The photoresponsivity (R) is assessed based on the impact of photon energies on the Jph values, with R values increasing from 7.2 to 8.0 mA/W as the wavelength decreases from 540 to 340 nm. Similarly, the detectivity (D) value increases from 0.164 × 10¹⁰ to 0.181 × 10¹⁰ Jones over the same wavelength range. At 730 nm, both R and D maintain substantial values of 6.4 mA/W and 0.145 × 10¹⁰ Jones, respectively. This fabricated optoelectronic device, with its excellent sensitivity, stability, reproducibility, low cost, and potential for mass production, holds significant promise for industrial applications as a highly effective photodetector.

Modulation depth and its associated loss pose a significant challenge in electro-optical telecommunication systems. Optimal modulators strive to enhance modulation depth while minimizing loss rates. We propose a high-performance electro-optical hybrid plasmonic modulator based on graphene, hexagonal Boron Nitride (h-BN), and Molybdenum Disulfide (MoS₂) layers. The substrate of the proposed modulator is SiO₂ on a Silicon wafer, where Ag layers are embedded in the SiO₂ layer and on top of the structure. Graphene layers at the edge of the upper and lower Ag layers and h-BN in between them create a waveguide capable of transmitting input light through the structure. Graphene and MoS₂ layers increase the amount of light interaction increasing, in turn, modulation depth. The edge mode in the graphene layers confines light properly and increases the electrical field intensity in a narrow gap. The modulator’s performance is examined using a three-dimensional finite-difference time-domain (FDTD) method. The structure’s modulation depth, for a range of temperature, ranges between 40.54 dB/μm and 42.05 dB/μm. The maximum loss is estimated to be 5.723 dB/μm at 1.3 μm for 0.65 eV chemical potential, which yields a figure of merit (FoM) of 12.5 and extinction ratio (ER) of 99.51 dB. The equivalent circuit for the modulator is investigated in terms of parameters such as energy consumption and modulation bandwidth. The modulator demonstrates an impressively low energy consumption per bit, underscoring its efficiency and practicality. The modulator’s characteristics primarily arise from utilizing a thin layer of h-BN instead of thick dielectric layers. Unlike the previously examined configurations, applying voltage through the graphene layers substantially diminishes the insertion loss.

A system of two cavities connected by a single-mode fiber is considered. We investigate the generation of bipartite entanglement between cavities by calculating bipartite negativity. We show that the phase transition point of PT-symmetry strongly depends on the phase factor characterizing the propagation of photons in the fiber. The range of that phase factor in which the system is in the unbroken phase of PT-symmetry is estimated. We also indicate that the entanglement between cavities depends not only on the gain and loss of energy in the system but also on that phase factor. In addition, we show that, under a fine-tuning of the phase factor, our system can be a source of maximally entangled states.

Perovskite solar cells (PSCs) have emerged as a viable contender for the third-generation solar cell, thanks to their exceptional characteristics involving high power conversion efficiency (PCE) and comparatively low fabrication costs. However, the challenges associated with interfacial recombination and poor device stability under operating conditions are still limiting their commercial viability. These challenges can be overcome by incorporating interfacial layers in order to enhance charge transport and reduce recombination losses. Herein, we introduce piperazine dihydriodide (PZDI) as an interfacial layer between the hematite electron transport layer (ETL) and absorber layer in PSCs. The high-quality PZDI layer further passivates surface defects and improves energy level alignment to facilitate more efficient charge extraction. The PCE was noted significantly higher by incorporation of the PZDI interfacial layer, reaching 17.5%, compared to 13.0% for the reference device without an interfacial layer. Long-term stability tests demonstrated that the target device retains 91.80% of its initial efficiency compared to 82.9% for the reference device after 500 h. These findings highlight the key function of the PZDI interfacial layer enhancing the photovoltaic (PV) performance of PSCs and can serve as crucial components in the development of long-lasting and high-efficiency PV.

Graphical abstract

In this paper, an integrable variant of the Manakov equation, called the shifted nonlocal Manakov equation, is investigated by proposing a novel improved Riemann–Hilbert (RH) approach. Firstly, the scattering-data constraints of the shifted nonlocal Manakov equation are shown to be difficult to determine via the traditional RH approach, which is different from the Manakov equation whose scattering-data constraints are easy to obtain in terms of the RH approach. Secondly, to overcome the difficulties in deriving the scattering-data constraints of the shifted nonlocal Manakov equation, the traditional RH approach is extended to a novel version which we call a novel improved RH approach. Specifically, utilizing the novel improved RH approach, the scattering-data constraints of the shifted nonlocal Manakov equation are obtained to guarantee the required shifted nonlocal symmetry reduction of the two-component Ablowitz–Kaup–Newell–Segur (AKNS) system. Moreover, the scattering-data constraints of the shifted nonlocal Manakov equation are compared with those of the Manakov equation. Thirdly, N-soliton solutions of the shifted nonlocal Manakov equation are derived by imposing the scattering-data constraints in those of the two-component AKNS system. The merits of our novel improved RH approach lie in two aspects, (i) it can be applied to those nonlocal soliton equations whose scattering-data constraints are difficult to obtain via the traditional RH approach, (ii) it does not require the complicated spectral analysis involved in the traditional RH approach. In addition, it is theoretically proved that the obtained soliton solutions can produce both globally regular solitary behaviors and finite-time collapsing periodic behaviors depending on the parameter selections obeying the scattering-data constraints. Furthermore, the two-soliton interaction dynamical behaviors are also investigated which exhibit spatially localized and temporally periodic breather features. Finally, the soliton dynamical behaviors are illustrated with a few graphical simulations.

A spiral-shaped photonic crystal fiber (SS-PCF) is described in this research report. Here, by using finer mesh, and finite element method (FEM), the fundamental properties of optical transmission, such as nonlinearity ((:gamma:)), birefringence (Br), beat length ((:{L}_{b})), confinement loss ((:{L}_{c})), numerical aperture (NA), effective mode area ((:{A}_{eff})) are derived for wavelength range from 0.1(:{upmu:}text{m}) to 1.5 (:{upmu:}text{m}.) Separately employed as core materials, Gallium phosphide (GaP), Graphene, and tellurite exhibit greater performance than that of earlier works. Graphene provides the extremely high nonlinearity of 6.13 × (:{10}^{12}) W^− 1km^− 1, GaP of 3.70 × (:{10}^{6}) W^− 1km^− 1 and tellurite of 3.28 × (:{10}^{5}) W^− 1km^− 1 at 0.1(::{upmu:}text{m}). To the best of our knowledge, an SS-PCF is the first to test the performance of numerous ceramic objects in optical nonlinear applications. In actuality, the structure’s evanescent fields aid in the modeling process and display a performance profile with an ultra-high Br of 0.33, an exceptionally high NA of 0.86, and an extremely low (:{L}_{c}) of 1.0 × (:{10}^{-5}) dBm^− 1. All these results might be crucial in biological imaging, sensing, supercontinuum applications, polarization maintenance, optical parameter amplification, and additional nonlinear applications.

This paper presents a novel transparent disc-shaped programmable antenna employing a polyimide substrate that exploits graphene parasitic elements to achieve programmable beamforming in sub-THz frequencies. The antenna consists of two orthogonal dipoles assisted by eight fan-blade-shaped graphene parasitic elements. By changing their state through chemical potential, the antenna current distribution is modified, enabling the formation of different radiation patterns such as single, dual, and quad beams. The inherent symmetry of the structure and that of the imposed programming codes is explained through the discussion of different radiation patterns generated in the azimuthal plane. The proposed antenna allows for discrete step beam reconfiguration over 360° in the azimuth plane. The maximum realized gain reaches 2 dBi for single beam, 1.3 dBi for dual beam and 0.7 dBi for quad beam configurations, accompanied by a minimum S₁₁ value of − 36.4 dB at 200 GHz and by a − 10 dB bandwidth ranges from 187 GHz to 214 GHz.

The nonlinear absorption coefficient (β) and nonlinear refractive index (n₂) of Carmine Encapsulation (CR-Cap) with H₂O/n-heptane/AOT solutions were investigated using a z-scan instrument. The transparent solution is made of water droplets containing carmine (CR), which are uniformly located in the continuous phase of n-heptane. The effects of Cetrimonium bromide (CTAB), NaCl, and NaOH on the β and n₂ values of CR in aqueous solution are studied and compared with CR-Cap. The values of β and n₂ for the CR-Cap have increased by 9 and 4.4 times, respectively, compared to those in its aqueous solution. The absorbance value and Rayleigh scattering (RS) change with environmental properties, while the optical gap is obtained as a constant 2.1 eV. The encapsulated CR has high RS and β values, which is caused by the increased polarizability of the molecule as a result of encapsulation, while aqueous solutions have low RS and β values. With quantum perturbation calculation, it is demonstrated that encapsulation increases the ground state dipole moment of CR compared to the aqueous solution. CR-Cap can be used as a photosensitizer in photodynamic therapy or optical devices.