A new carborane-containing metal-organic framework (Cb Ni-MOF) was synthesized using a high-power laser-assisted method. The material was prepared from Nickel(II) chloride hexahydrate (NiCI2 center dot 6H(2)O) and m-carborane-1,7-dicarboxylic acid (Cb). FTIR spectroscopy-based structural analysis confirmed successful coordination between the carborane carboxylate groups and Ni(II) ions. SEM-based morphological description revealed 200 nm to 1 mu m-sized polyhedral particles, indicating a crystalline and porous nature. TEM images further revealed nanoscale crystallinity with particle diameters around 50 nm, together with single-/polycrystalline structures with identical features. These findings demonstrate that the laser-assisted process is efficient for preparing nano-ordered, highly crystalline Cb-based MOFs. In this work, the generation of a high-performance ultrafast fiber laser system at the 2- mu m wavelength region was demonstrated. The system utilized a passively mode-locked oscillator incorporating a Cb Ni-MOF deposited on an arc-shaped fiber, demonstrating exceptional nonlinear optical properties with 14.1% modulation depth and 11.2 MW/cm(2) saturation intensity. The laser oscillator generated ultrashort pulses with a duration of 1.2 ps at a center wavelength of 1942.9 nm. Using a chirped pulse amplification (CPA) technique with pre-amplification and main amplification stages, the high-power fiber laser achieves remarkable performance characteristics: 8.4 W average output power, 264 fs pulse duration, 433 nJ pulse energy, and 1.64 MW peak power at 19.4 MHz repetition rate. This high-power ultrafast fiber laser system shows significant potential for applications in invasive medical procedures, advanced material processing, and other fields requiring precise and high-intensity laser-matter interactions.

Surface plasmon resonance (SPR) is a common technique used for the real-time tracing of various analytes through refractive index-dependent resonance shifts. However, many plasmonic biosensors do not meet the clinical detection requirements for ultra-low concentration and low refractive index biomarkers. To address this challenge, researchers have explored unique labeling and interface modification strategies. One common strategy is utilizing fluorescence with plasmonic structures and enhancing the fluorescence intensity. However, these studies primarily focused on plasmon-enhanced fluorescence intensity, leaving the influence of fluorophores on reflection-/absorption-based plasmonic resonance shifts unexplored. Herein, we introduce a technique for amplifying the resonance shift of a plasmonic metasurface by confining the interdistance of fluorescence emitters. By adjusting nanospaces (∼4 to 20 nm), we couple surface plasmons with fluorescence in the near-field, achieving interdistance-dependent resonance shift behavior. This approach results in a 4.5-fold signal enhancement in the resonance shift for detecting conjugated proteins from complex matrices. In this regard, we utilize a plasmonic metasurface and distinct fluorescent emitters (FITC, Texas Red, streptavidin-quantum dot (QD) 525, and streptavidin-QD 625) with diverse excitation and emission assets. We also experimentally demonstrate a spectral blue shift of the plasmonic resonance through resonant coupling between QDs and surface plasmons, in contrast to the conventionally observed red shift. To hurdle the cost- and fabrication-related challenges in metasurfaces, we recycle off-the-shelf digital versatile discs (DVDs) into plasmonic metasurfaces due to their intrinsic nanograting structures, thereby significantly minimizing the cost down to $1.5. Moreover, we collect spatiotemporal signals using a palm-sized platform (5 cm × 10 cm x 1 cm) within 15 min that would be easily adapted into any settings possible. Consequently, this strategy paves the way for creating novel configurations and arrangements on a metasurface sensor to couple with fluorescence molecules while boosting the sensor's analytical performance that would be potentially integrated with biosensing applications in disease diagnostics.

Metal-organic bimetallic frameworks of Ni-Co, having metal content of 2:1 and 1:2 molar ratios, respectively, have been synthesized via a rapid laser method with a continuous-wave Nd:YVO4 laser (λ = 975 nm) under 88-90 °C in a DMF/H2O solution in 70 min. The structure, porosity, and photophysical, electrochemical, and dielectric characteristics of the frameworks and their reduced graphene oxide (rGO) composites in the form of powders and UV-cured PEGMEA/PEGDA films have been investigated. Framework Ni2Co1MOF demonstrated a BET surface area equal to 88.3 m2 g-1 and a total pore volume of 0.022 cm3 g-1, whereas framework Ni1Co2MOF exhibited a BET surface area of 52.5 m2 g-1 and a total pore volume of 0.016 cm3 g-1. The incorporation of rGO from 1 to 10 wt.% into the framework changed the charge transport and polarization properties of the materials. The electrochemical investigations of the 10 wt.% rGO-Ni1Co2MOF composite in 0.5 M HCl demonstrated a specific capacitance of 32.3 F g-1 at 10 mV s-1, and it preserved 98% of the electrochemical response after 400 cycles, in comparison with 96% for the 10 wt.% rGO-Ni2Co1MOF. The electrochemical responses consisted of both diffusion-controlled ion transport and pseudocapacitance. The introduction of rGO in 1 to 10 wt.% in the polymer composite improved the conductivity and Maxwell-Wagner-Sillars interface polarization at low frequencies in the case of low rGO concentrations, whereas overly high rGO content led to aggregation and the decreased influence of the conductive phase. The main contribution of the present work is the fast sub-100 °C synthesis approach for compositionally tunable Ni-Co frameworks/rGO materials and the relationships between the metal ratio, porous structure, interfacial charge transport, and dielectric response.

Radiation science has a wide range of applications, from industrial uses and medical treatments to space research and national defense. Optical fiber technology offers a flexible and sensitive alternative solution for accurate radiation measurements in various applications. This study presents a new sensor design based on Yb-doped optical fibers for gamma radiation detection. The behavior of Yb-doped fibers under gamma irradiation was investigated, and a sensor was developed based on the red (or blue) shift in fluorescence emission. Three homemade and two commercial Yb-doped optical fibers were irradiated to different total doses of gamma radiation, then excited with UV light to record their spectra. A red-shift (or blue-shift in doped with Al and without P) was observed with increasing radiation dose, attributed to the formation of color centers in the fiber. These spectral shifts depend on the fiber composition and radiation dose. The highest sensitivity was observed in Fiber-3HM and Fiber-5HM which are highly radiation-sensitive, and online radiation monitoring has sensitivity as high as 7.56 nm kGy ^−1 and 3.65 nm kGy ^−1 . For the first time, we have demonstrated a radiation sensor based on the principle of fluorescence emission shift induced by the applied radiation dose, as described in the existing literature.

A rapid, high-yield laser-assisted synthesis route with an exceptional production efficiency (>= 90%) is introduced for cobalt-based metal-organic frameworks (Co-MOFs), producing ordered hybrid structures within an hour that integrate optical, magnetic, and adsorption functionalities. The Co-MOFs exhibit tunable properties, including a low-temperature paramagnetic transition confirmed by magnetic measurements and first-principles calculations. Gas adsorption studies reveal promising performance for N2, CH4, and CO2, combining low energy consumption with cost-effective gas separation. Structural analysis indicates mesoporosity with high accessibility, supporting selective uptake under practical conditions. Importantly, Co-MOF-modified graphite electrodes demonstrate outstanding electrochemical sensing performance for dopamine, achieving a low detection limit (5.5 & micro;M), high sensitivity (121 & micro;A mM- 1 cm- 2), and excellent reproducibility in human serum. These results underline the multifunctional potential of laser-synthesized Co-MOFs as scalable platforms that couple sustainable gas separation with biomedical diagnostics, advancing the development of framework materials for real-world applications.

The incorporation of silicon oxynitride (SiON) into silicon (Si) allows us to create a unique material in the field of Si photonics with tunable optical properties [1]. Conventional materials like SixNy, SiOxNy, and Si-rich Si3N4 are utilized for their mechanical robustness, thermal stability, chemical resistance, electrical insulation, and optical transparency [2], [3]. This study presents innovative advancements in silicon photonics through the synthesis of silicon oxynitride-doped silicon (SiON-doped Si) on flexible substrates, enabling the development of distributed Bragg gratings (BGs) for anti-counterfeiting applications. Utilizing a modified plasma-enhanced chemical vapor deposition system, we achieved low-temperature fabrication of SiON-doped Si, which exhibits a refractive index range from 2.1 to 2.5 at the wavelength of 1310 nm and unique photosensitivity properties across various wavelengths. Our research demonstrates that these flexible BGs can be inscribed with femtosecond laser light, allowing for the encoding of micro-information that is observable under specific viewing angles and light conditions due to change in the absorption of the photosensitive SiON-doped Si thin films layers. The structural integrity and optical characteristics of the BGs were thoroughly analyzed using soft X-ray absorption spectroscopy, Raman spectroscopy, and grazing incidence X-ray diffraction, confirming their potential for high-performance applications in lasers and spectrometers. The findings indicate that the incorporation of SiON-doped Si in wearable technologies not only enhances authentication mechanisms but also opens new avenues for versatile optical devices. This work lays the groundwork for future explorations into advanced materials systems in silicon photonics [4], emphasizing the role of SiON-doped Si in enhancing security features in consumer products.

Mode-locked fiber lasers are particularly noteworthy due to their compactness, affordability, and reduced losses, making them an attractive option for a variety of uses. Metal-organic frameworks (MOFs) have recently been identified as suitable saturable absorbers (SAs) in lasers operating at 1.5- and 2 μm wavelengths [1], [2]. MOFs represent a novel class of porous solid materials formed by the combination of inorganic metal ions and organic linkers. These frameworks exhibit exceptional material properties, such as a large surface area, structural diversity, tunable bandgap, and luminescence, making them highly advantageous for various applications in laser technology. This work presents an ultrafast mode-locked fiber laser operating in the relatively less explored O-band region, utilizing a nickel MOF (Ni-MOF) as a saturable absorber.

In this study, a copper-based metal–organic framework (Cu-MOF) was synthesized using terephthalic acid (TPA, H2L), 1,2-bis(4-pyridyl)ethene (bpe) as organic binders, and Cu2+ ions, to act as a saturable absorber (SA) material. The SA was fabricated by depositing Cu-MOF on an arc-shaped fiber, and was then incorporated into a thulium-doped fiber laser (TDFL) and a holmium-doped fiber laser (HDFL), with both achieving stable mode-locking operation. The SA exhibited a modulation depth of 5.7

This chapter reviews the synthesis, properties, and applications of metal and metal oxide nanoparticles, as well as MOFs, produced using high-power lasers. The integration of MOFs and nanometals is further explored in cutting-edge applications including photocatalysis, gas sensing, supercapacitors, lithium-ion batteries, and solar energy conversion. Special attention is given to defect engineering, 3D laser printing of MOF composites, and emerging photothermal and optoelectronic functionalities. These techniques enable precise control over nanoparticle size, morphology, and composition, and significantly reduce reaction times for MOF formation. Our experimental results on laser ablation and the nanoparticle size distributions are provided in detail. For example, with a pulsed laser ablation energy of 70 mJ, the zinc oxide nanoparticle’s (ZnO NPs) size distribution produced an average nanoparticle size of 12.2 nm. Furthermore, the fast and scalable synthesis of MOFs employing laser irradiation techniques is extensively discussed for several uses in state-of-the-art technology. This work provides an explanation for high-power laser-induced rapid synthesis (LIRS) of Ni- and Zn-based MOFs achieved in a far shorter time and with higher yields than earlier reported techniques. Promising supercapacitor technologies, the chapter covers Cu-MOF/PANI- and Cu-MOF/PPy-based nanocomposites with high particular capacitance. The specific capacitance values are 160.5 F/g for Cu-MOF/PANI and 132.5 F/g for Cu-MOF/PPy nanocomposites, respectively. The activity of the Pt@UiO-66-NH2 MOF nanocomposite was discovered among the investigated to be 257.38 mmol g−1 h−1.

MXenes have been demonstrated as saturable absorbers for mode-locking in fiber laser systems operating from 1 to 2 mu m wavelength. Despite that, there has been no utilization of MXene as a mode-locker at the extended 2 mu m wavelength. In this work, we present the potential of MXene material (Cr2C) for mode-locking in a Holmiumdoped fiber laser (HDFL). The Cr2C-SA had a saturation intensity of 1.7 MW/cm2 and a modulation depth of 14.2 %, respectively. Stable fundamental mode-locked pulses were realized at the pump power of 1.6 W. The mode-locked pulses had a repetition rate of 13.74 MHz, centered at 2077.54 nm, with a pulse duration of 1.75 ps. This study presented the first HDFL system to use MXene as a saturable absorber and the first utilization of Cr2C as a mode-locker.

Pure nickel-based metal-organic frameworks (Ni-MOFs) are prepared primarily using mechanochemical synthesis, hydrothermal, and solvothermal procedures. Upon synthesizing MOFs using these traditional methods, the additional laser processing step was applied to MOF derivatives for the features of engineering structural defects and their applications in the fields of catalysis, environmental protection, and energy [1], [2].

Specialty fibers are designed as a diverse and innovative class of optical waveguides that meet specific performance criteria beyond those of standard telecom fibers. These designs are engineered with advanced materials possessing unique structures, compositions, or geometry for various industrial applications such as sensing. For instance, rare Earth (RE) elements such as Yb, Er, Nd, and Tm have been incorporated into the core of optical fibers for high-power fiber laser applications due to their strong absorption and emission bands. Yb-doped optical fibers exhibit high quantum efficiency, which facilitates the production of high-power fiber lasers with optical-optical efficiencies reaching around 90%. However, radiation-induced defects occur due to irradiation, leading to a degradation of beam quality. Yb-doped fibers are susceptible to degradation from radiation sources such as high-energy particles and gamma rays [2], which results in a loss of performance in optical transmission and light amplification. This type of degradation is referred to as radiation-induced attenuation (RIA), as the formation of color centers directly affects the transmission properties of optical fibers, consequently leading to a decline in their performance.

Pump combiners are essential components used to merge the power from pump diodes in high-power fiber laser oscillator and amplifier systems. A popular method for fabricating these pump combiners, which includes signal feedthrough, is the fused taper fiber bundle. This technique utilizes an end pump approach where the signal fibers are also tapered alongside the pump fibers [1]. However, with this type of combiner, pumping can only occur in one direction. Recently, it has been demonstrated that counter-pumping or bi-directional pumping mechanisms allow for increased power scaling and lower nonlinear interaction thresholds. These interactions include phenomena such as Stimulated Raman Scattering and, more critically, Transverse Mode Instability [2]. An alternative to the end pumping technique that facilitates both counter and bi-directional pumping is the side coupler technique. In this method, the fiber core remains uninterrupted, allowing for greater flexibility in positioning the pump fiber points compared to the end pumping approach. The most widely used fabrication technique for side pump combiners is the direct fusion method, which is favored for its suitability in high-power laser operations [3], [4]. This technique effectively combines the advantages of side coupling with the ability to scale power while maintaining beam quality. With this motivation, we aimed to fabricate a high-power side pump combiner using a homemade passive large-pitch photonic crystal fiber (LPF).

Pyrene-functionalized poly(epsilon-caprolactone) (Py(PCL)), poly(L-lactide) (Py(PLLA)) homopolymers, and an AB-type block copolymer (Py(PCL-b-PLLA)) are synthesized via ring-opening polymerization (ROP) using Sn(Oct)2 catalyst with epsilon-CL and L-LA monomers. Structural characterization is confirmed by FTIR, 1H NMR, and XRD analyses, while thermal and optical properties are assessed using TGA, DSC, UV-vis, and photoluminescence spectroscopy. The polymers exhibited strong photoluminescence across 380-700 nm, high thermal stability, and nanostructured surface morphology as revealed by SEM and 3D laser microscopy. Biocompatibility is evaluated by culturing MCF-7 breast cancer cells on polymer-coated glass slides. The materials supported uniform cell distribution, robust adhesion, and sustained viability and proliferation. These results highlight the polymers' suitability for tissue engineering and biomaterials research. The incorporation of pyrene units enabled intrinsic fluorescence tracking, positioning these polymers as multifunctional platforms for applications in cancer research, real-time bioimaging, and regenerative medicine. By combining fluorescence capability with biodegradability and promotion of cell growth, Py(PCL), Py(PLLA), and Py(PCL-b-PLLA) offer a promising, environmentally friendly approach bridging imaging and therapeutic delivery needs in biomedical applications.

The fabrication processes of single transverse mode passive large-pitch optical fiber (LPF) have been proposed and investigated. The LPF design, combined with the fundamental mode operating principle of delocalizing higher-order modes, has led to impressive performance. In this study, two LPF preform designs were proposed based on the stacking of one type of inner glass tube, two (design of LPF1) or three (design of LPF2) different filler rods, and a core rod placed within an outer tube. The first passive LPF1 is fabricated from a single-step preform drawing process. This fiber exhibits single transverse mode propagation, featuring a core size of 45.5 µm and a normalized hole diameter of 0.454. For the first time, a single transverse mode of light propagation from an LPF with an elliptical-like hole shape was achieved. The second LPF2 design has been proposed and fabricated by using a two-step preform drawing process. Successful production of an LPF with a circular hole shape has been obtained and exhibits single transverse mode propagation, featuring a core size of 42.8 µm and a normalized hole diameter of 0.322. Furthermore, numerical analysis was also performed to study mode propagation for the LPF.

We report a case study of the experimentally observed negative shift for the Copper nanoparticle colloids (NPs) when they are kept in contact with a quartz interface. This investigation is based on the previously reported measurements on various volumetric concentrations of Cu NPs using the Terahertz Time-Domain Spectroscopy (THz-TDS) technique. A gradually increasing negative time shift reminiscent of a superluminal propagation was observed for the Cu NPs in contrast with Ag NPs. In this work, we explain the possible reason for such observation by quantifying the recorded negative delays with high precision and by modelling the THz peak profiles under the assumption of a thin film formation at the dielectric colloid interface. Cu nanoparticle colloids with the same specifications were produced under the same conditions to verify the effect of the quartz interfacial layer. Quartz slides were kept immersed inside the colloids for up to 3 days and periodically monitored using UV-visible spectroscopy technique. While the Ag NPs did not show any evidence of thin film formation, the Surface Plasmon resonance absorption peaks were measured for Cu NPs, proving a thin layer formation on the slide surface. Our findings explain the advanced phase shift occurring at the dielectric-conductor interface which is valid only when the electromagnetic field transmits into the absorbing medium in the presence of a thin conducting layer.