Wavelength Range Research Articles

Review of: "the nanoparticle field is comparable to the energy of electromagnetic radiation and if significant changes are made in a certain wavelength range"

Review of: "the nanoparticle field is comparable to the energy of electromagnetic radiation and if significant changes are made in a certain wavelength range"

Review of: "electromagnetic radiation and if significant changes are made in a certain wavelength range with the occurrence of chemical reactions in the irradiated materials, the activity of nanoparticles up to 100nm will be significant"

Review of: "electromagnetic radiation and if significant changes are made in a certain wavelength range with the occurrence of chemical reactions in the irradiated materials, the activity of nanoparticles up to 100nm will be significant"

Regulation of eumelanogenesis-related genes by ethanol extract of Melaleuca Leucadendron leaves.

Eumelanin, a type of skin melanin pigment, possesses the ability to absorb a wide range of wavelengths, providing protection to the skin from ultraviolet radiation. However, excessive production of eumelanin may result in hyperpigmentation. Consequently, the development of skin-brightening products that suppress eumelanin synthesis to achieve a lighter and more even skin tone is necessary. The present study investigated the potential application of Melaleuca leucadendron as a natural skin-brightening agent. We investigated the effects of the ethanol leaf extract of M. Leucadendron on α-melanocyte-stimulating hormone-induced melanogenesis in B16F10 cells and identified the key factors involved in melanogenesis. This leaf extract significantly inhibited melanin production by downregulating the expression of microphthalmia-associated transcription factor, tyrosinase, tyrosinase-related protein 1, and dopachrome tautomerase without causing cytotoxicity. Furthermore, it substantially reduced melanin content in a 3D skin model. These results suggest that the extract of M. Leucadendron is a promising, safe, and effective skin-brightening agent.

Stretchable Ag2S-MXene Photodetector Designed for Enhanced Electrical Durability and High Sensitivity.

In this work, we present a facile and straightforward approach for fabricating highly stretchable photodetectors based on Ag2S and Ti3C2Tx MXene hybrid materials. These devices exhibit exceptional mechanical resilience, maintaining stable electrical and optical performance even after 10 000 cycles of 30% strain. The incorporation of MXene not only enhances the device's electrical durability but also ensures the retention of conductivity under significant mechanical deformation, positioning MXene as a critical material for the advancement of flexible electronics. These devices demonstrate strong photoresponses across a broad wavelength range, from visible to infrared, confirming their potential for use in flexible and stretchable optoelectronic applications. This study highlights the advantage of utilizing MXene in stretchable electronics and offers a promising route for developing durable, flexible devices for next-generation wearable technologies.

Fabrication, characterization and performance analysis of sol–gel dip coated SnO2 thin film

Transparent conducting oxide (TCO) is widely utilized in various fields of electronics and optoelectronics, including touch-screen technology, thin-film solar cells, dye-synthesized solar cells (DSSC), and more. Yet, the costs associated with TCO films can be substantial, for instance, roughly 40% of the total expenses of the dye-synthesized solar cells are due to the use of this component. Therefore, fabricating TCO using Tin oxide (SnO2) using the sol–gel dip coating method is the central theme of this study. Where emphasis has been given to attaining high performance using locally available low-cost materials in Bangladesh. Moreover, to find out the electrical and optical properties of the fabricated SnO2 thin film UV spectroscopy, energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), four-point probe measurement, and thickness measurement have been done. In addition, uniformity and cracks in the crystals, and morphological images have been observed using scanning electron microscopy (SEM). A thin layer with a thickness of 144 nm and a resistivity of 2.27 Ω-cm has been created after 16 times dipping in sol–gel solution. The findings indicate that the thin films have an average transmittance of roughly 70% in the 300–1200 nm wavelength range. Furthermore, the outcome also reveals that the thin films’ average band gap is approximately 3.533 eV. The experimentally obtained data have been included in the simulation for performance analysis. As demonstrated by the simulation, by using this TCO, a maximum efficiency of 17.525% may be attained in a CdTe solar cell. If manufactured correctly, SnO2 TCO could potentially rival traditional FTO or ITO based TCOs in solar cell research.

Cavity Wavelength on Erbium-Doped Fiber Ring Laser Depending on Fabry–Pérot Etalon Steering Angle

This study presents the liquid crystal Fabry–Pérot etalon (LC-FP) as the preferred laser wavelength tuning solution within a erbium-doped fiber ring laser architecture. The laser cavity wavelength can be adjusted by applying varying voltages to the LC-FP. Furthermore, tuning the laser wavelength can be facilitated by modifying the incident light through changes in the steering angle of the LC-FP, which is attributed to the angular dispersion characteristics of the device. The operational range for the steering angle of the LC-FP is ± 4 to 18 degrees. This architectural framework is adept at facilitating the generation of single-wavelength and dual-wavelength lasers within the C band. The tunable range for a single wavelength is approximately 13 nm, while the tunable range for dual wavelengths is around 14 nm, with a wavelength spacing of approximately 17.5 nm. These capabilities are primarily influenced by the operational wavelength of the erbium-doped fiber amplifier (EDFA), the operating wavelength of the collimator that directs the fiber optic beam into the LC-FP, and the fixed thickness of the LC-FP.

A Design Study on Polarized Beam Splitter for Visible Light

This study employs the thin film design software TFCale to successfully design and realize a high-efficiency polarization beam splitter suitable for the visible light wavelength range of 400-700 nm, with incident angles between 40 and 50. The design objective was to achieve near 100% reflectance for S-polarized light and near 100% transmittance for P-polarized light. By optimizing the refractive index, thickness, and multilayer structure of the thin film materials, we achieved high-performance optical characteristics. During the design process, we conducted an in-depth investigation of the optical constants of various materials and combined the interference effects of multilayer films to ensure the desired polarization splitting effect within the specified range of incident angles. Simulation results indicate that the film exhibits high-efficiency polarization separation across the entire visible spectrum: the reflectance of S-polarized light remains above 80% within a certain angular range, and the transmittance of P-polarized light also remains above 80%. This high-efficiency polarization beam splitter has broad application prospects in optical instruments, laser systems, display technologies, and other fields requiring precise polarization control. Its superior performance not only enhances the efficiency and accuracy of optical systems but also provides valuable references for future optical thin film design. The study demonstrates that using TFCale for thin film design is an effective method to meet complex optical performance requirements and offers reliable solutions for practical applications

A promising high-sensitive 1D photonic crystal magnetic field sensor based on the coupling of Fano\\Tamm resonance in far IR region

This paper presents a novel investigation of a magnetic sensor that employs Fano/Tamm resonance within the photonic band gap of a one-dimensional crystal structure. The design incorporates a thin layer of gold (Au) alongside a periodic arrangement of Tantalum pentoxide () and Cesium iodide () in the configuration . We utilized the transfer matrix method in conjunction with the Drude model to analyze the formation of Fano/Tamm states and the permittivity of the metallic layer, respectively. These states can be manipulated based on the left-handed and right-handed circular polarization of electromagnetic waves, along with an applied magnetic field. Several key parameters were optimized, including material selection, layer thickness, unit cell periodicity, and the angle of incidence, to enhance the sensor performance. Additionally, we investigated how variations in magnetic field strength influence the position of Fano/Tamm resonance in the reflectivity spectrum of the interacting electromagnetic waves within a specific wavelength range of 60 μm to 140 μm. The proposed sensor displays good performance investigated by calculating several parameters like, sensitivity, figure of merit, quality factor and resolution. One of them, it shows a maximum sensitivity of 57 nm/Tesla within a magnetic field strength of 20 to 140 Tesla, positioning it as a promising candidate for various applications in magnetic field measurement and telecommunications, particularly in the unique far-infrared region.

Acousto-optically induced single-frequency Nd:YAG ring laser based on double corner cube retroreflectors

Using an acousto-optic modulator (AOM) to enforce the unidirectional operation of a Nd:YAG ring laser based on double corner cube retroreflectors (CCRs) was demonstrated for the first time, to the best of our knowledge. By tilting the AOM with RF applied to deviate from the Bragg angle, a different diffraction loss was introduced between the counterpropagating beams in the ring cavity. A continuous wave single-frequency laser with a maximum output power of 2.99 W was successfully obtained at 1064.5 nm, with a tunable wavelength range from 1064.3 nm to 1064.7 nm. The experimental results indicated the unidirectional operated ring cavity comprising the double CCRs performed significant tolerance to the misalignment of the cavity. By changing the RF to pulsed mode and adjusting the angle of the AOM closer to the Bragg angle, the unidirectional Q-switched operation was achieved with the increase of the diffraction loss of the oscillating light. At the repetition frequency of 110 Hz, a 0.882 mJ single-frequency pulse energy with a pulse width of 70.2 ns was obtained, corresponding to a peak power of 12.6 kW. Sngle-frequency pulses with energy of 0.761 mJ and pulse width of 72.4 ns were also obtained at the repetition frequency of 1 kHz, corresponding to a peak power of 10.5 kW.

Waveguide adapter with contactless flange for operation in the millimeter wavelength range

Waveguide adapter with contactless flange for operation in the millimeter wavelength range

Chalcogenide dual-core all-solid anti-resonant fiber polarization beam splitter operating at 3 μm band

Abstract For the first time, we proposed a polarization beam splitter (PBS) designed based on chalcogenide dual-core all-solid anti-resonance fiber (AS-ARF) and simulated it numerically using the finite element method (FEM). Two large cladding tubes are introduced to divide the fiber core into fiber cores A and B. Mode coupling and energy exchange between the two fiber cores are enabled through the gap g between the two large cladding tubes. By adjusting the structural parameters of the AS-ARF, polarization beam-splitting ability and single-mode characteristics can be obtained. The influence of the position of the nested tube within the large cladding tube on the performance of the PBS is further investigated. The numerical results show that the beam-splitting lengths of the two proposed PBSs are 9.5 cm and 8.2 cm, respectively, and the polarization extinction ratios (PERs) are −55.98 dB and −41.35 dB at 3 μm. In the wavelength range from 2.98 μm to 3.03 μm, both PBSs can simultaneously achieve polarization beam-splitting and single-mode characteristics. The proposed chalcogenide-based dual-core AS-ARF is a suitable candidate for PBS in the mid-infrared 3 μm band.

Bioinspired broadband antireflection coatings on silicon wafers enabled by a polyimide-assisted self-masking technique.

Here we report a simple self-masking technique for fabricating bioinspired broadband antireflection coatings on both single-crystalline and multicrystalline silicon wafers with the assistance of a polyimide tape. Subwavelength-structured moth-eye nanopillars, which exhibit superior antireflection performance over a broad range of visible and near-IR wavelengths, can be patterned uniformly on the wafer surface by applying a chlorine-based reactive ion etching (RIE) process. The resulting random nanopillars show improved antireflection properties compared with ordered nanopillars templated by colloidal lithography under the same RIE conditions. X-ray photoelectron spectroscopy analysis suggests that energetic bombardment by reactive ions and radicals during RIE sputters the polyimide tape and spontaneously forms nanomasks over the wafer.

Effect of MgCl2 dopant on optical properties of tamarind gum based biopolymer electrolytes

Recent research on biopolymers based on magnesium salts is scarce in the existing literature. In the current research study, solution-casting technique was used for the preparation of solid biopolymer electrolytes, using Tamarind Seed Polysaccharide (TSP) as the host biopolymer, which was doped with several varying concentrations of magnesium chloride (MgCl2). UV-visible spectroscopic method was used to investigate the thermal and optical parameters in the wavelength range of 200 nm to 800 nm. From the study of optical absorption parameter, the values of optical transmission, optical refractive index, optical absorption coefficient and optical extinction coefficient were calculated. These parameters revealed optimum values for the film of composition TSP:MgCl2 (70:30 wt.%).

Manipulating continuous optical spectra in the wave vector domain by metalens.

Complete 2π cycling of a phase around a phase singularity leads to a rapid phase variation in the nearby zones and forms a sharp local k-vector peak. In this paper, the intensity distribution in the spatial domain is transformed into a k-vector distribution in the wave vector domain, and we prove that the local k-vector peak is generated at the point of minimum light field intensity. The local k-vector peak is sharper when the minimum point is closer to the phase singularity. The k-vector peak can be manipulated by controlling the minimum optical field intensity. A metalens is designed to generate sharp k-vector peaks for continuous wavelengths and linearly shift the positions of these peaks with the incident wavelength. This method transforms full-band continuous optical spectra from the spatial domain to the wave vector domain. The spectral resolutions over the wavelength range from 800 nm to 810 nm are less than 0.82 nm, and the optimal spectral resolution reaches 0.027 nm. This approach can be used in metasurface spectroscopy, providing what we believe to be a new way to improve spectral resolution.

The James Webb Space Telescope Absolute Flux Calibration. III. Mid-infrared Instrument Medium Resolution Integral Field Unit Spectrometer

Abstract We describe the spectrophotometric calibration of the Mid-Infrared Instrument’s (MIRI) Medium Resolution Spectrometer (MRS) aboard the James Webb Space Telescope. This calibration is complicated by a time-dependent evolution in the effective throughput of the MRS; this evolution is strongest at long wavelengths, approximately a factor of 2 at 25 μm over the first 2 yr of the mission. We model and correct for this evolution through regular observations of internal calibration lamps. Pixel flat fields are constructed from observations of the infrared-bright planetary nebula NGC 7027, and photometric aperture corrections from a combination of theoretical models and observations of bright standard stars. We tie the 5–18 μm flux calibration to high signal-to-noise ratio (S/N; ∼600–1000) observations of the O9 V star 10 Lacertae, scaled to the average calibration factor of nine other spectrophotometric standards. We calibrate the 18–28 μm spectral range using a combination of observations of main belt asteroid 515 Athalia and the circumstellar disk around young stellar object SAO 206462. The photometric repeatability is stable to better than 1% in the wavelength range 5–18 μm, and the S/N ratio of the delivered spectra is consistent between bootstrapped measurements, pipeline estimates, and theoretical predictions. The MRS point-source calibration agrees with that of the MIRI imager to within 1% from 7 to 21 μm and is approximately 1% fainter than prior Spitzer observations, while the extended source calibration agrees well with prior Cassini Composite Infrared Spectrometer and Voyager Infrared Interferometer Spectrometer and Radiometer observations.

The Photoinduced Response of Antimony from Femtoseconds to Minutes.

As a phase change material (PCM), antimony exhibits a set of desirable properties that make it an interesting candidate for photonic memory applications. These include a large optical contrast between crystalline and amorphous solid states over a wide wavelength range. Switching between the states is possible on nanosecond timescales by applying short heating pulses. The glass state is reached through melting and rapid quenching through a supercooled liquid regime. While initial and final states are easily characterized, little is known about the optical properties on the path to forming a glass. Here we resolve the entire switching cycle of antimony with femtosecond resolution in stroboscopic optical pump-probe measurements and combine the experimental results with ab-initio molecular dynamics simulations. The glass formation process of antimony is revealed to be a complex multi-step process, where the intermediate transient states exhibit distinct optical properties with even larger contrasts than those observed between crystal and glass. The provided quantitative understanding forms the basis for exploitation in high bandwidth photonicapplications.

Deposition of plasmonic ITO nanoparticles by near-infrared laser ablation

Compound nanoparticles (NPs) attract attention because of their unique electrical, optical, and catalytic properties. Among them, plasmonic tin-doped indium oxide (ITO) NPs are characterized by transparency in the visible wavelength range and tunable localized surface plasmon resonance (LSPR) in the near-infrared (NIR) range due to high electronic conductivity. To date, they have been usually synthesized by a chemical solution process. However, the chemically synthesized ITO NPs are capped with organic protecting agents, which often block exchange of charge carriers and access of chemical species to the NPs, limiting some applications. In the present study, we propose a method for direct deposition of ITO NPs on a glass or plastic substrate using commercially available ITO-coated glass via NIR laser ablation. The LSPR characteristics of the ITO NPs, thus, prepared were controlled by changing the ablation conditions such as laser power. In addition, the potential applications of the ITO NPs were also investigated through measurements of their refractive index sensitivity and magnetic circular dichroism.

Low-Temperature Growth of Centimeter-Sized 2D PdSe2 by Self-Limiting Liquid-Phase Edge Epitaxy.

Two-dimensional (2D) PdSe2 atomic crystals hold great potential for optoelectronic applications due to their bipolar electrical characteristics, tunable bandgap, high electron mobility, and exceptional air stability. Nevertheless, the scalable synthesis of large-area, high-quality 2D PdSe2 crystals using chemical vapor deposition (CVD) remains a significant challenge. Here, we present a self-limiting liquid-phase edge-epitaxy (SLE) low-temperature growth method to achieve high-quality, centimeter-sized PdSe2 films with single-crystal domain areas exceeding 30 μm. The SLE growth mechanism, clarified by theoretical calculations and time-of-flight secondary ion mass spectrometry (ToF-SIMS), reveals that hydrogen ions on the precursor surface inhibit vertical growth while promoting lateral growth. The as-grown PdSe2 few-layer exhibits a surface roughness of 1.20 nm and an average conductivity of 1.67 × 10-6 S/m, demonstrating their smoothness and uniformity. Temperature-dependent electrical measurements and transfer characteristic curves confirm the orthorhombic PdSe2's bipolar semiconductor behavior. The photodetector based on few-layer PdSe2 films exhibit excellent optoelectronic performance in the 405-1650 nm wavelength range, achieving a responsivity of 6262.37 A W-1, a detectivity of ∼1012 Jones under 1064 nm illumination, and a fast response time of 37.1 μs, making them highly suitable for broadband photodetection applications. This work provides valuable insights into the scalable synthesis of PdSe2 few-layers and establishes a foundation for the development of PdSe2-based integrated functional devices.

Carbon Dots@Upconversion Nanoparticles: Conjugate Manipulation and Luminophor Confinement Enabling Aqueous-Phase Orthogonal Multicolor Phosphorescence-Upconversion Luminescence.

Developing single-particle nanocomposite with aqueous-phase orthogonal multicolor phosphorescence or multimodal luminescence holds great significance for optical coding, anti-counterfeiting encryption, bioimaging, and biosensing. However, it faces challenges such as a limited range of emission wavelengths and difficulties in controlling the synthesis process. In this work, a conjugate structure manipulation integrated luminophor confinement strategy is proposed to prepare carbon dots@upconversion nanoparticles (CDs@UCNPs) featuring aqueous-phase orthogonal multicolor room-temperature phosphorescence-upconversion luminescence (RTP-UCL) through wet-chemical synthetic methods. Four types of CDs are synthesized by introducing molecules with varying degrees of conjugation, while the intersystem crossing process is enhanced by constructing charge-transfer states to narrow the energy gap between the excited singlet and triplet states. Aqueous-phase orthogonal multicolor RTP (green, yellow, and orange) and UCL (blue, green, yellow, and red) are achieved by confining CDs with different conjugation degrees within a NaBiF4 matrix doped with various lanthanide ions. Notably, NaBiF4 UCNPs can crystallize at low temperatures, serving as a matrix to immobilize CDs, thereby preventing their vibration and rotation, and minimizing interference from water and oxygen. Additionally, the versatility of this strategy is demonstrated by constructing multicolor CDs@Cs2NaGdCl6: 5%Yb3+,10%Er3+ perovskite nanocomposites. This strategy offers valuable guidance for the preparation of advanced aqueous-phase orthogonal multicolor materials.

Small-angle neutron scattering differentiates molecular-level structural models of nanoparticle interfaces.

The highly anisotropic and nonadditive nature of nanoparticle surfaces restricts their characterization by limited types of techniques that can reach atomic or molecular resolution. While small-angle neutron scattering (SANS) is a unique tool for analyzing complex systems, it has been traditionally considered a low-resolution method due to its limited scattering vector range and wide wavelength spread. In this article, we present a novel perspective on SANS by showcasing its exceptional capability to provide molecular-level insights into nanoparticle interfaces. We report a series of experiments on multicomponent nanoparticles, where we demonstrate the ability of SANS to differentiate between competing structural models with molecular- and Å-scale differences. The results provide accurate quantification of organic ligand chain lengths, nanoparticles' heterogeneity, and detailed structures of surrounding counter-ion layers in solution. Furthermore, we show that SANS can probe subtle variations in self-assembled monolayer structures in different thermodynamic states. Our findings challenge the conventional view of SANS as a low-resolution technique for nanoparticle characterization and demonstrate its unique potential for providing molecular-level insights into complex nanoparticle surface structures.