Optical and Quantum Electronics最新文献

The addition of Acridine orange (AO) dye to a polymer blend (80% PVA-20% PVP) enhances its optical, electrical, and radiation attenuation properties, which is a promising approach for polymer applications in nuclear radiation shielding. The effects of acridine orange (AO) dye inclusion on the structure of (PVA- PVP) polymer films, as well as their optic, dielectric, and shielding properties, are studied in this paper. The effect of the Acridine orange (AO) dye on the lattice of the (PVA- PVP) blend is also investigated. With increased AO dye concentration in the UV–Vis range (200–600 nm), UV–Vis absorption spectroscopy shows a greater absorption of the composites. The reduction in hybrid film bandgap due to localized states in the forbidden region makes the current films suitable for optoelectronic, solar cell, and other applications. Composite films have proven to be effective as high-power laser blocking filters in a variety of wavelength ranges. At room temperature, the dielectric constant ε^’, dielectric loss ε″ and ac conductivity σ_ac were examined with frequency (100 Hz–1 MHz) and AO dye concentration. The addition of AO dye increases the σac of the (PVA-PVP) blend, which is used in various semiconductor devices. The radiation attenuation qualities were studied using the Phy-X/ PSD program. All radiation shielding characteristics are highly dependent on the density and doping AO dye content in the blend polymeric matrix. Our findings revealed that the rising reinforcement ratio of AO dye has a direct relationship with the analyzed parameters. The preceding investigations into the behavior of doped materials by AO dye have led to the conclusion that AO dye is a useful multifunctional technique that enhances the optical and individual radiation attenuation characteristics of (PVA-PVP) polymers.

Mercury (Hg²⁺) and lead (Pb²⁺) are among the most hazardous heavy metals, so effective monitoring systems for their detection in water are needed to protect environment and public health. This study numerically explores a dual-channel surface plasmon resonance (SPR) sensor based on a uniform-waist tapered optical fiber, designed to detect Hg²⁺ and Pb²⁺ simultaneously. Sensing channels are engineered with different thin-film metal coatings and optimized taper ratios. One channel incorporates MoS₂ over a silver film, while the other used graphene over gold, both utilizing the strong adsorption capability of 2D materials. The sensor’s performance is evaluated across a sensing medium refractive index (SMRI) range of 1.333–1.342. After structural optimization, the sensor is evaluated for the simultaneous detection of Hg²⁺ and Pb²⁺ ions within concentration range of 70 to 1000 ppm. The sensor achieved a maximum sensitivity of 0.0242 nm/ppm for Hg²⁺ with a corresponding detection limit of 21.56 ppm, while the recorded sensitivity and detection limit for Pb²⁺ were 0.0251 nm/ppm and 19.17 ppm, respectively. The proposed dual-channel tapered SPR configuration presents a compact, cost-effective, and highly sensitive platform for the detection of heavy metals.

Breast cancer cells 4T1 cells exhibit a negative surface charge characteristic to most cancer cells due to the movement of mobile ions across the cell membrane. They are effectively damaged by photodynamic action using polycationic photosensitizers. Photosensitizers based on long-wavelength polycationic phthalocyanines demonstrate stability of their optical properties on a wide range of concentrations, high in vitro phototoxicity in the nanomole range due high extinction and quantum yield of reactive oxygen species, as well as effective binding of polycationic PS molecules to the surface of tumor cells. The studied PSs proved to be very effective for photodynamic therapy against breast cancer cells 4T1 and exhibited complete photodestruction of the cells at nanomolar concentrations.

A flexible microfiber sensor for pressure and temperature dual parameter sensing is proposed in this paper. The optical fiber is composed of a balloon-shaped silicon dioxide core and polymethyl methacrylate (PMMA) cladding doped with CdZnSe/ZnSe/ZnS quantum dots. It uses flexible polydimethylsiloxane (PDMS) as the packaging layer and has a high softness. The experimental results show that the pressure sensitivity of the sensor can reach 0.249 nm/mN. The cross-sensitivity problem is solved by discussing the interference of temperature on both the transmission spectrum and fluorescence wavelength simultaneously. This has broad development prospects in the fields of micro force sensing and micro machinery.

Atrazine is one of the most widely used herbicides, but its persistence in soil and water poses significant risks, necessitating the development of rapid and selective detection methods. A one-dimensional photonic crystal (1D-PC) sensor is proposed, composed of alternating titanium dioxide ((text {TiO}_2)) and silicon dioxide ((text {SiO}_2)) layers with an embedded defect layer of a molecularly imprinted polymer (MIP) specific to atrazine. The periodic structure provides a photonic band gap (PBG), where the MIP layer introduces a sharp resonant transmission mode. Binding of atrazine molecules alters the MIP’s effective refractive index, producing a measurable shift in the resonant wavelength. Using the transfer matrix method (TMM), the transmission spectra was modeled to evaluate performance metrics such as sensitivity, quality factor, and figure of merit. The results demonstrate a distinct resonance shift with increasing analyte concentration, enabling selective, high-resolution optical detection. Unlike conventional designs, the critical role of oblique incidence in maximizing the Figure of Merit is identified, and a comprehensive tolerance analysis is incorporated to validate the sensor’s practical feasibility against fabrication errors. Compared to complex inverse-opal or porous structures, this planar (text {TiO}_2)/(text {SiO}_2) design offers advantages in fabrication simplicity and integration into compact optical platforms. A foundation for developing low-cost, highly selective photonic sensors for monitoring environmental contaminants is established by this study.

We present a method for obtaining the leaky modes and their losses in arbitrary leaky fiber structures. We first obtain the guided part of a leaky mode as a ‘limiting’ guided mode of the core structure of the fiber. Next, the ‘limiting’ guided mode is propagated through the actual leaky fiber to obtain the propagation loss. In this way we obtain the real and imaginary parts of the effective index of the leaky mode. Traditionally, the complex effective index has been obtained either by direct solutions of the complex eigenvalue equation which often presents convergence difficulties, or by involved computations in the transfer matrix method (TMM) to obtain a particular functional behavior of the field characteristics as a function of the propagation constant values to obtain the peak position and the width of the obtained function which give, respectively, the real and imaginary parts of the propagation constant. Our method involves only real eigenvalue problem and straightforward numerical propagation of the field. The method works for all modes and for any arbitrary fiber. Comparison with the available results shows the effectivity and applicability of the method.

Although natural extracts have recently been explored as low-cost active layers for photodetectors, most reported devices still suffer from low photocurrent generation and inefficient charge separation at the organic/inorganic interface. A key research gap is the lack of high-performance Hesperis matronalis subsp. matronalis L. extract (HSPR)/silicon heterojunctions that can overcome these limitations and demonstrate competitive responsivity and detectivity. HSPR was obtained by aqueous extraction method. The prepared extract was coated on Si wafers by spin coating method. The dark I–V curves of the HSPR@p-Si heterostructure displayed a significant rectification characteristics. I–V measurements of the HSPR@p-Si heterostructure were carried out under white light, 365 (UV), 590 (yellow) and 850 nm (IR) lights, and in all cases the device showed typical photodetector behavior. The maximum R of > 4.54 A/W and D* of ~ 1 × 10¹² Jones are determined at a wavelength of 590 nm. Furthermore, the highest value of NPDR, NEP and EQE, were ~ 2.1 × 10⁷ W⁻¹, ~ 2 × 10⁻¹² WH^−0.5 and ~ 932(%), at 590 nm under the power intensity of 8 mW/cm². Additionally, the device maintained its stability after 30 days in room environment without any encapsulation. HSPR’s strong interaction with light has led to the conclusion that it could open new doors for optoelectronic applications in the future.

The article investigates the frequency shifting of a laser carrying orbital angular momentum (OAM) in a cold collisionless plasma under the impact of a static magnetic field applied in the axial direction. Spatio-temporal variation of the laser intensity profile is investigated considering relativistic mass increase of the plasma electrons. Nonlinear Schrodinger equation is derived using Wentzel -Kramers - Brillouin (WKB) method and slowly varying envelope approximation. The frequency shifting is then discussed in connection with the spatio-temporal variation of the laser intensity. The effects of magnetic field along with the effects of the polarization states are discussed in detail. The relativistic frequency shifting is observed to enhance both rear side and front side of the pulse with the applied magnetic field. It is also observed that right circularly polarized (RCP) lasers undergo stronger shifting than the left circularly polarized (LCP) lasers. The results obtained in this article may find application in twisted harmonic generation, particle acceleration, optical manipulation and so on.

In this study, an antireflection (AR) coating based on SiO₂ was controllably deposited using a computer-programmed CNC system and evaluated for its performance. A unique, automated high-precision technique was employed for AR layer deposition. Transmission and reflectance measurements were conducted using a UV–Vis spectrophotometer, while the photocatalytic performance of the AR layers was assessed using a methylene blue dye solution under UV illumination. The AR-coated glass was mounted on a monocrystalline silicon solar cell, and the I-V and P-V characteristic curves were obtained. The best-performing AR-coated solar cell exhibited an open-circuit voltage (V_oc) of 0.61 V and a short-circuit current density (I_sc) of 41.6 mA/cm², resulting in a 2% increase in efficiency compared to the uncoated device. The CNC-controlled deposition process enabled precise tuning of parameters such as immersion speed, withdrawal speed, dwell time, and alignment, ensuring uniform coatings and enhanced optical performance. Field tests confirmed the low reflectance and improved efficiency of AR-coated solar panels. These findings highlight the potential of SiO₂-based AR coatings for enhancing solar cell performance while maintaining mechanical stability.

This paper explores the sensing capabilities of one-dimensional (1-D) photonic crystals (PC) based on the thermo-optic effect in alternating layers of Gallium Nitride (GaN) and Silicon Nitride (Si₃N₄) with double defect layers of air under the application of very high temperatures, ranging from 1000℃ to 1700℃ in 50℃ temperature increments. The proposed new structure of double defect layers enhances sensing efficiency by generating two distinct resonance modes. The principle of the 1-D PC is explained by its optical behaviour, specifically photonic band gap (PBG) without and with defect layers. The temperature sensing efficiency is developed by adding defect layers in the PC, which enables it to transmit two resonance peaks due to double defect layers. The transmission and reflection behaviour of PC is plotted using the computational method, and the numerical values of the proposed sensor are calculated by the well-known transfer matrix method (TMM), resulting in the effective parameters like sensitivity, quality factor (Q-factor), full width at half maxima (FWHM) of the PC. The sensitivity of the sensor for mode − 1 is approximately 0.008 nm/℃, while the sensitivity for mode − 2 is about 0.014 nm/℃. The FWHM of the resonance peaks for mode − 1 and mode-2 are 6.3 nm and 10.832 nm, respectively, at a temperature of 1000℃. The Q-factors for mode − 1 and mode − 2 are 158.512 and 125.802, respectively, at 1000℃.