Optical Applications Research Articles

Structural, electronic, and optical-absorption properties of 2D Si thin films

AbstractRecent experimental studies highlighted the potential of thin-film crystalline silicon (Si) for high-efficiency solar cells. Using density functional theory, we investigated 2D Si thin films across various orientations, thicknesses, and surface structures to elucidate their structure–property relationships. Through surface-energy calculations and Wulff construction, we determined the crystal habit of Si, which aligns with available experimental observations. Electronic-structure calculations underscored the critical role of valence saturation on surfaces in enabling semiconducting behavior in Si thin films, essential for optical applications. From optical-absorption calculations, we identified the surface index exhibiting the highest absorption coefficients for thin films Si solar cell applications. Graphical abstract

Optical Applications of CuInSe2 Colloidal Quantum Dots.

The distinctive chemical, physical, electrical, and optical properties of semiconductor quantum dots (QDs) make them a highly fascinating nanomaterial that has been extensively studied. The CuInSe2 (CIS) QDs demonstrates great potential as a nontoxic alternative to CdSe and PbSe QDs for realizing high-performance solution-processed semiconductor devices. The CIS QDs show strong light absorption and bright emission across the visible and infrared spectrum and have been designed to exhibit optical gain. The special characteristics of these properties are of great significance in the fields of solar energy conversion, display, and electronic devices. Here, we present a comprehensive overview of the potential applications of colloidal CIS QDs in various fields, with a particular focus on solar energy conversion (such as QD solar cells, QD-sensitized solar cells, and QD luminescence solar concentrators), solar-to-hydrogen production (such as photocatalytic and photoelectrochemical H2 production), and QD electronics (such as QD transistors, QD light-emitting diodes, and QD photodetectors). Furthermore, we offer our insights into the current challenges and future opportunities associated with CIS QDs for further research.

Introduction of a modified anomalous vortex beam with self-focusing properties

This study introduces and experimentally demonstrates the concept of a modified anomalous vortex beam (MAVB), which carries orbital angular momentum (OAM) and exhibits unique self–focusing properties. By utilizing holographic techniques and customizing phase masks, we precisely control the beam’s phase and intensity distribution, enhancing self-focusing behavior while preserving traditional anomalous vortex beam features. We derive an analytical formula to describe MAVB propagation within a paraxial ABCD optical system. The self–focusing characteristics are influenced by initial parameters such as beam order, quantum number, beam waist, wavelength, and the modification parameter. Additionally, we simulate MAVB propagation and their OAM spectrum in maritime atmospheric turbulence. Through comprehensive theoretical analysis and experimental validation, we show how MAVBs achieve controlled self–focusing, leading to enhanced beam control and stability. Our study explores the mechanisms, design principles, and practical implications of MAVBs, emphasizing their potential to revolutionize optical applications.

Optical transmission, dielectric constants, and gamma shielding performance of Se95-xIn5Prx metallic alloys: Radiation protection applications

Due to the high density of metals, metallic materials such as alloys have the potential to have high gamma-radiation-absorbing abilities. This would make them relevant in a radiation environment as either a shielding material or a radiation sensor. These would, however, depend on their gamma radiation responses. Research aimed at evaluating the gamma response parameters of different glassy alloys that have technical applications is scarce compared to the traditional characterization with respect to optical features, structural evolution, and mechanical strength. In this paper, the optical and radiation shielding abilities of Se95-xIn5Prx (x = 2, 4, and 6) glassy alloys were investigated using standard theoretical techniques. The mass attenuation coefficient (MAC) of the materials was computed using the XCOM software. Reflection loss values are 0.20218, 0.22634, and 0.22908 for SIPr1, SIPr2, and SIPr3, respectively, while the optical transmittance values are 0.66365, 0.63087, and 0.62723 in the same order. The metallization criterion declined when Pr increased in the alloy. The values of MAC ranged from 0.0317 cm2/g to 98.2099 cm2/g for SIPr1, 0.0319 cm2/g to 97.3798 cm2/g for SIPr2 and 0.0322 cm2/g to 96.5372 cm2/g for SIPr3. The Higher attenuation and absorption coefficients were found for Pr-rich alloys. Pr therefore increase the ability of the SIPr-alloy to attenuate and absorb photon energy. The optical parameters of the investigated alloys could be used to identify their optical applications. SIPr3 had comparatively higher shielding ability compared to some known shields and could thus be used for radiation control and protection purposes.

Impact of gamma irradiation on optical and nonlinear properties of Indium chloride phthalocyanine thin films

This study investigates the impact of gamma radiation on indium chloride phthalocyanine (lnPcCl) thin films, which were prepared via vacuum thermal evaporation. x-ray diffraction revealed the amorphous structure of the films, with increasing gamma doses causing more noticeable structural disorders. Optical analysis showed a slight decrease in the optical band gap energy and a significant reduction in the fundamental band gap energy. Additionally, higher gamma doses led to decreased transmittance and increased reflectance. The study also observed substantial enhancements in nonlinear optical parameters, such as third-order nonlinear susceptibility (χ(3)) and nonlinear refractive index (n 2). These findings suggest the potential of gamma-irradiated lnPcCl films for advanced optoelectronic and nonlinear optical applications.

Industrial picosecond pulse laser welding of stainless-steel to quartz for optical applications

We report on the development of a robust picosecond laser welding process for the industrially relevant material combination of quartz and stainless steel. The process requires high numerical aperture focusing of a 6 ps 1030 nm laser through the transparent quartz onto the interface between the two materials. It is found that increased mechanical pressure applied during welding increases reliability and weld performance and with the correct choice of welding parameters parts will survive ISO standard thermal cycling and vibration testing demonstrating the suitability of the process for industrial application.

Optical sensing and nonlinear optical properties of Cr-doped MoO3/PEDOT:PSS Nanocomposites

In this study, we observed a negative UV photoresponse that switched to a positive photoresponse in Cr-doped MoO3/PEDOT:PSS nanocomposite films(NCF) prepared via drop-casting. MoO3 and Cr-doped MoO3 were synthesized using a hot oil bath co-precipitation method, combined with PEDOT:PSS (poly(3,4-ethylenedioxythiophene) doped with poly(4-styrenesulfonate)), and coated onto flexible OHP sheets. The open aperture z-scan method investigated the nonlinear optical properties of NCF on the glass substrate. The films were characterized by X-ray diffraction, scanning electron microscopic (SEM), UV–Vis spectroscopy, and Fourier Transformed Infrared (FTIR). Chromium doping caused minor changes in lattice parameters, crystalline size, and microstrain. UV spectroscopy revealed an increase in bandgap with higher Cr–MoO3 concentrations. The photoresponse of different Cr–MoO3 concentrations showed an initial current decrease under UV light, but the photoresponse became positive beyond a threshold and continued to improve. Nonlinear optical studies indicated saturable absorption in the nanocomposite. This work enhances our understanding of Cr-doped MoO3/PEDOT:PSS nanocomposites, contributing to advancements in flexible UV photodetectors and nonlinear optical applications.

Versatile Nanolights From Silicon, Carbon and Oxygen Hybrid System for Optical Applications

AbstractSilicon, carbon and oxygen hybrid nanomaterials (i.e., SiCOHNs) have recently drawn extensive attention as versatile photoluminescence (PL) nanosystems. The collective advantages of silicon‐ and carbon‐based nanostructures have resulted in SiCOHNs with tunable and photostable PL properties, abundant possibilities for surface modification, and low biotoxicity. Although SiCOHNs have shown great potential in diverse applications, such as bioimaging, biosensing, drug delivery and information encryption, discovering novel SiCOHNs with explicit nanostructures and elucidating the fundamental mechanisms of their PL properties for bioapplications are highly desirable. In this review, on the preparation of SiCOHNs on the basis of the synthesis conditions and precursors are first focused. Next, the manipulation of the emission wavelength, quantum yield and RTP of SiCOHNs is discussed. On the basis of previous reports and the recent experimental/theoretical results, the primary structure of SiCOHNs is clarified and deduced their possible PL mechanism. SiCOHNs possess bacterial uptake efficiency and/or anticancer capacity, promoting various biomedical applications and proof‐of‐concept applications in anti‐counterfeiting. Finally, current challenges and future trends are summarized as a roadmap for the development of SiCOHNs‐based optical applications.

Prediction of 2D XC2N4 (X= Ti, Mo, and W) monolayers with high mobility as an encouraging candidate for photovoltaic devices

In this study, the impacts of strain and an electric field on the electronic and optical characteristics of monolayer XC2N4 (X=Ti, Mo, and W) were systematically examined using the density functional theory. The results corroborated that the dynamically, mechanically, and thermodynamically stable XC2N4 monolayers displayed semiconductor properties when the Heyd-Scuseria-Ernzerhof (HSE06) method was used. The TiC2N4 monolayer is shown to be a direct-gap semiconductor of 1.179 eV whereas the MoC2N4 and WC2N4 monolayers are indicated to have indirect bandgaps of 2.819 eV and 2.661 eV, respectively. Notably, the TiC2N4, WC2N4, and MoC2N4 monolayers possess comparatively high electron mobilities of 2776.85 cm2/V s, 1576.79 cm2/V s, and 1316.41 cm2/V s, respectively. The influence of strain on the bandgap of the MoC2N4 and WC2N4 monolayers led to a decrease in their gap, whereas in the TiC2N4 monolayer, the applied tensile strain caused an increase in the bandgap. Moreover, the compressive strain significantly caused a transition from semiconducting to metallic characteristics (zero band gap). The optical absorption spectra indicated the existence of three separate maxima for the XC2N4 (X=Ti, Mo, and W) monolayers with an extreme intensity of up to 2.0 × 105 cm−1. Interestingly, compared with pure monolayers, strained monolayers enhance the beginning of coefficient absorption in the visible range, with widespread range absorption in the ultraviolet and visible regions. Our results suggest that these monolayers can be promising options for nanoelectronic, optical and photovoltaic applications.

A Highly Optical Anisotropic Hybrid Metal Halide for Modulation and Generation of Polarized Light

AbstractPolarized light is critical for a wide range of applications in modern optics. However, its generation and modulation typically require additional optical comments, which hinders device compactness. Herein, an air‐stable Tin(IV)‐based hybrid metal halide, (C10H9N2O)2SnCl6, composed of [C10H9N2O]+ cations and isolated [SnCl6]2− octahedra is reported. Notably, (C10H9N2O)2SnCl6 exhibits a robust birefringence of 0.50@550 nm that is evidently larger than those of commercially used crystals, which enables efficient modulation of polarized light. Moreover, it possesses a broad polarized blue emission in the range of 374–600 nm with a peak at 426 nm. Theoretical and structural studies reveal that the high optical anisotropy for large birefringence and directly polarized emission of (C10H9N2O)2SnCl6 is ascribed to the cooperative effect of distortion of [SnCl6]2− and high π‐conjugation of [C10H9N2O]+ in parallel arrangement. This work may provide new thoughts on designing and realizing the miniaturization of polarization‐resolved optoelectronic devices.

An efficient and improved algorithm for generating an equivalent planar architecture of the data vortex switch

The data vortex (DV) switch was originally designed as an all optical interconnection network for high performance computing (HPC) applications. It was highly scalable with low latency and high throughput, compared to traditional switches used for optical packet switching (OPS) and HPC applications. The equivalent planar (chained MIN) model of the DV, proposed in previous literature, is a planar diagrammatic conversion of a 3-D model of the DV network. In this paper, we will focus on exploring a new, efficient and improved generalized algorithm that enables the arrangement of routing pathways to be implemented as an equivalent planar architecture (EPA, chained MIN) of a DV to find all possible routes between each source and target node pair. The original 3-D architecture of any size can be converted to a planar structure more simply by using the new generalized equivalent planar architecture (EPA) algorithm. To verify the proposed EPA algorithm, it was tested with different input traffic loads and network sizes while keeping the active angle ‘A’ constant. Network performance parameters, including injection rate (throughput) and latency (mean hops), obtained from simulation results are also provided to confirm the validity of the proposed EPA algorithm. This new algorithm is versatile, simple and can be applied to networks of various sizes.

Effect of annealing on ion-beam-sputtered hafnium oxide thin films properties

HfO2 films are high laser damage-threshold and low-absorption thin-films that can be utilized for a broad range of optoelectronic and optical applications. In this study, HfO2 thin films were prepared via dual ion beam sputtering followed by annealing in the atmosphere at temperatures ranging from 200 to 700 °C. The optical properties, microstructure, film stress, and absorption loss of the HfO2 films at various annealing temperatures were then systematically characterized. The results revealed that the properties of the films were improved after annealing at temperatures below 500 °C. Specifically, at an optimal annealing temperature of 400 °C, the residual stress of the films was minimized close to zero and the absorption loss was as low as 1 ppm. However, at annealing temperatures reaching 600 °C, the films began to crystallize, leading to the deterioration of their optical properties. Optimizing the process parameters for HfO2 thin film deposition is crucial for developing the next generation of high-performance laser optics.

SO3NH3 crystal growth in (CH3)3SBr solution

SO3NH3 (Sulfamic acid, or SA) is known for its excellent piezoelectric and optical properties, making it valuable for various optical applications. However, it usually takes weeks to months to grow the SA single crystals with centimeter-scale size by traditional growth method from solution. In this study, we use (CH3)3SBr (Me3SBr) as an additive to enhance the growth rate of SA single crystals, and the growth time was reduced to just 48 h. The mechanism of accelerated crystallization process is attributed to the variations of electrostatic potential and binding energy on SA crystal modified by the additive. In addition, structural analysis and basic characterization on the newly grown SA are performed, and first-principles calculations provide insights into the energy band structure and phonon spectrum.

Retraction Note: Optical medical equipment application and observing the occurrence of hypotension in elderly patients after general anesthesia induction through arteriovenous ultrasound parameters

Retraction Note: Optical medical equipment application and observing the occurrence of hypotension in elderly patients after general anesthesia induction through arteriovenous ultrasound parameters

Fe3+ Assisted Synthesis of Stable 3D‐in‐2D CsPbBr3/CsPb2Br5 Nanocomposites for Optical Gain Media

AbstractMetal halide perovskite nanocrystals are sought after for many optical and optoelectronic applications, such as light‐emitting diode and solar cells, due to their outstanding optical properties. However, their ionic nature makes them susceptible to ambient conditions. One rational solution to this challenge is the passivation or encapsulation of perovskite nanocrystals to isolate them from their environments. Thus, there is an urgent need to develop efficient methods for encapsulating emissive perovskite nanocrystals. A facile post‐synthesis method is proposed to treat CsxFA(1−x)PbBr3 nanocrystals, in the presence of Fe3+ cations, to create a robust and water‐stable nanocomposite structure, where 3D CsPbBr3 nanocrystals are embedded in and thus protected by the 2D CsPb2Br5 nanosheets (named as CsPbBr3/CsPb2Br5 hereafter). These Fe3+ cations facilitate the formation of the CsPbBr3/CsPb2Br5 composite and regulate the growth of 2D CsPb2Br5 sheets. By performing controlled experiments, the possible mechanism of 2D nanosheet growth is proposed and discussed in detail. More importantly, the composite can remain stable in water for three months and exhibits amplified spontaneous emission under femtosecond laser irradiation. This work presents a synthesis pathway for producing durable perovskite composites that are promising for future lasing applications.

All–polarization maintained erbium-doped nonlinear amplifying loop mirror mode-locked fiber laser for optical frequency comb application

All–polarization maintained erbium-doped nonlinear amplifying loop mirror mode-locked fiber laser for optical frequency comb application

A Low-Hydroxyl Quartz Glass Prepared by Using a Plasma Heat Source as the Flame and High-Purity Quartz Sand as the Raw Material

In this paper, a quartz glass with low hydroxyl groups was prepared by combining the advantages of various processes, using a plasma heat source as the flame and high-purity quartz sand as the raw material. The purity of the quartz sand was 99.997%. The number of air bubbles in the quartz glass prepared using high-purity quartz sand was lower. The hardness and tensile strength of the quartz glass were 737.7–767.1 GPa and 6.88–9.64 MPa, respectively. The hydroxyl content of the sample was only 4.11 ppm, and the hydroxyl content of the homogenized quartz glass was reduced to 2.64 ppm, which was an improvement of about 35%. After homogenization, the fictive temperature (Tf) of the quartz glass was determined to be 1253 cm−1, and the variation of the Tf value along the radial direction was reduced, indicating a more homogeneous glass structure. The stress distribution in the quartz glass was significantly improved. These results indicate that the preparation of quartz glass from high-purity quartz sand using a plasma heat source as the flame opens up new avenues for optical applications.

Coordinative Polyimides‐Ln3+ for Full‐Spectrum Luminescence with Applications in PLEDs and Acid‐Responsive Data Encryption

AbstractControllable coordination and efficient sensitization of rare earth ions in polymer materials are key to achieving high‐performance optoelectronic polymers. By designing aromatic diamines, polyimides are synthesized with 1,10‐phenanthroline benzimidazole groups (PBG) in the polymer backbone. Utilizing the coordination between PBG and rare earth ions (Eu3⁺, Tb3⁺), polyimide‐rare earth complexes are formed and precisely characterized their structures. The unique coordination allows PBG to effectively sensitize Eu3⁺, resulting in efficient, long‐lived red emission. Furthermore, PBG maintains excellent coordination with Eu3⁺ in acidic environments, granting acid‐responsive color changes for data encryption. Importantly, PBG sensitization of Tb3⁺ enabled full‐spectrum emission (CIE coordinates: (0.31, 0.35)) within a single rare earth‐polyimide complex, due to electron transfer among the ions, ligands, and polymer. This leads to the design of a multi‐layer PLED device with an optimal external quantum efficiency of 0.43% for white light emission (CIE coordinates: (0.28, 0.34)). Through comparative theoretical and experimental analysis, the photophysical behavior of these coordinated polyimides is explained and explored their photoluminescent and electroluminescent properties. This research integrates the advantages of rare earth elements and polyimides, creating novel luminescent polymers with diverse optical applications, providing a new strategy for designing luminescent coordination polymers.

Core-shell nanomaterials based on La2FeCrO6 coated with metal oxides for optical applications

In this research work, the preparation of core/shell nanoparticles comprising La2FeCrO6 (LFCO) as the core was accompanied by the choice of ZnO and CuO as different shells. Structural and optical characteristics were investigated for the LFCO (core) relative to La2FeCrO6/ZnO and La2FeCrO6/CuO core/shell NPs. x-ray diffraction analyses reveal the conformation of core/shell structures within average crystallite sizes of 22.46 nm and 25.03 nm. Raman spectroscopy and Fourier-transform infrared spectroscopy (FTIR) were performed to provide fundamental information about the vibrational modes and the functional groups of core/shell NPs, respectively. x-ray photoelectron spectroscopy (XPS) detects the electronic states of the constituent elements of the core/shell nanostructures, including lanthanum, iron, chromium, oxygen, zinc, and copper. Optical characteristics have been extensively analyzed using UV spectroscopy. The energy gap (Eg) was determined by utilizing both Tauc and Derivation of Absorbance Spectrum Fitting (DASF) methods. LFCO/ZnO and LFCO/CuO core/shell NPs exhibit a direct optical transition, similar to that of the core LFCO NPs, with a decrease in band gap value from 3.4 eV for the core to 3.3 eV and 3.18 eV for LFCO/ZnO and LFCO/CuO core/shell NPs respectively. The enhanced transparency of core/shell NPs, particularly at longer wavelengths, is evident from the decrease in refractive index (n) compared to that of the core (LFCO) NPs. This decrease is attributed to the encapsulation of LFCO with either ZnO or CuO NPs. The samples exhibit a decline in both linear and non-linear optical susceptibilities with respect to the square of photon energy. The LFCO/CuO sample shows excellent results in the photocatalytic degradation of aqueous organic dyes, considering it a promising candidate for wastewater treatment and the removal of organic pollutants.

Unravelling Optoelectronic and Transport Properties in RuZrX (X=Si, Ge) Alloys: Insights from DFT

AbstractThe structural, mechanical, electronic, and thermoelectric properties of RuZrSi and RuZrGe half‐Heusler alloys were thoroughly examined using the full‐potential linearized augmented plane‐wave (FP‐LAPW) method within the WIEN2k code, based on Density Functional Theory (DFT). The study utilized the Perdew‐Burke‐Ernzerhof generalized gradient approximation (GGA‐PBE) and the Tran‐Blaha‐Johnson (TB‐mBJ) approximations for the exchange‐correlation potential. The findings reveal that both alloys are semiconductors with indirect band gaps, and they are ductile, anisotropic, and mechanically stable. These properties make them suitable for various practical applications. The electronic analysis confirms the semiconducting nature of RuZrSi and RuZrGe due to their indirect band gaps. Mechanically, both alloys show ductility and stability, enhancing their potential usability. Additionally, their thermoelectric properties are notable, with high Seebeck coefficients (S) and a significant figure of merit (ZT), indicating strong performance in thermoelectric devices. Optical properties, including the dielectric function and absorption coefficients, suggest these materials have considerable potential for photovoltaic and optical applications, especially in the UV and visible light spectrum. While these results are promising, experimental validation is required to confirm the theoretical predictions made in this study.