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Laser-stimulated piezo-optical and third harmonic generation studies for Na2O–Sb2O3 glass ceramics-influence of gold ions
摘要： Sodium antimonate glass ceramics with different concentrations of Au2O3 were synthesized. The prepared samples were characterized by XRD, XPS, SEM and TEM techniques. These studies have revealed that the samples consist of multiple crystalline phases composed of Sb3+, Sb5+, Au3+ ions, and Au0 particles; moreover these studies have indicated growing proportion of Au0 particles and Sb5+crystal phases (Na2Sb2O6) with increase of Au2O3 concentration. IR and Raman spectral studies have pointed out an increasing degree of polymerization of the glass network with increase of Au2O3 content while optical absorption studies indicated surface plasmon resonance effects. Nd: YAG laser (λ = 1320?nm and pulse width 8?ns) was used for inducing third harmonic generation (THG) signal. Later, THG signal intensity of Nd: YAG laser (λ = 1064?nm and pulse width of 20?ns) vs fundamental beam power density was recorded. The results indicated the maximum intensity for the samples containing a low concentration of Au2O3. For inducing piezo-optical effects, Nd: YAG laser (λ = 1064?nm) and its doubled frequency beam λ = 532?nm (with simultaneous mechanical pressure) were used. The cw He-Ne laser of 20?mW (with beam diameter about 0.5?mm) was used as probing beam for measuring the piezo-optical effects in the photo-polarized samples. The variation of the intensity of the THG beam and piezo-optical coefficients were found to be the maximal for the samples mixed with small quantities of Au2O3. The detailed analysis of XRD, SEM, EPR, IR, optical absorption spectral results suggested that concentrations of Na3SbO3 and also Au2O3 crystal phases are maximal in these?samples and are responsible for the maximal photoinduced effects, while the increasing presence of Na2Sb2O6 crystal phases and Au0 metallic particles are found to be hindrance for generation of third harmonic beams and also piezo-optical effects. Overall, the obtained results of nonlinear optical (NLO) and piezo-optical studies indicated that Na2O-Sb2O3 glass ceramics containing small traces of Au2O3 are useful for considering them for nonlinear optical triggering devices and piezo-electric devices.
关键词： Sodium antimonate glass ceramics,piezo-optical effects,Nd: YAG laser,Au2O3,third harmonic generation
更新于2025-09-11 14:15:04
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Treatment of lichen pilaris with a Q-switched Nd:YAG laser in quasi long-pulsed mode: A case report (a secondary publication)
摘要： Background and Aims: Lichen pilaris is a very common disease typically seen among young adults on their upper arms as a manifestation of hyperkeratotic lesions occurring in the pores. Only a few treatments have been reported as significantly effective, so often natural resolution over time is the only option. The present study examined the use of a 1064 nm Q-switched Nd:YAG laser (QSNY) in quasi long-pulsed mode, in an attempt to treat a case of lichen pilaris. Subject and Methods: A 33-year-old male presented with light-brown aggregated papules observed on both sides of the upper arms. The affected areas were treated every other week (QSNY, pulse width 300 μs, pulse energy 3.0 J/cm2, spot size 6 mm and repetition rate 10 Hz). Clinical photography was taken of the lesions at baseline and three months after the final treatment in addition to macrophotography and 3-D photography, biopsies being taken at both time points for histological comparison. Results: The clinical photography and objective image evaluation demonstrated shrinkage of pores and improvement of the unevenness of the skin. Histological examination suggested that the effect of the micropulsed QSNY on the horny layer, epidermal keratinocytes and dermal collagen resulted in a peeling effect and increased dermal collagen density, which eventually led to the shrinkage of the pores and improvement of the skin condition. Conclusions: The results of this single patient case report suggest that the micropulsed QSNY could be an effective treatment option for lichen pilaris, improvement of which is often difficult. Further studies with an appropriately-sized population are merited to confirm these preliminary results.
关键词： Q-switched Nd:YAG Laser,Lichen pilaris,Histological examination,Quasi long-pulsed mode
更新于2025-09-11 14:15:04
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Tunable three-level Nd:YAG CW laser with three lowest wavelengths at 869, 875, and 878 nm
摘要： We present a tunable three-level Nd:YAG laser using a birefringent filter (BF) based on the 4F3/2?4I9/2 transition, generally used for a 946 nm emission. Three-level Nd:YAG laser was performed at three different laser wavelengths of 869 (pure-three-level), 875 (pure-three-level), and 878 nm (quasi-three-level). Within three wavelengths, the 875 and 878 nm were demonstrated for what is believed to be the first time. The highest output power of 1.21 W was achieved at 869 nm with a slope efficiency of 9.9%. Moreover, a continuous-wave (CW) simultaneous dual-wavelength Nd:YAG laser at 875 and 878 nm was also demonstrated for the first time.
关键词： Tunable,Pure-three-level laser,Solid-state laser,Nd:YAG
更新于2025-09-11 14:15:04
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Reflections on the Er:YAG Laser Used in “Nonthermal Mode” to Rejuvenate Skin
摘要： CO2 and Er:YAG lasers are both actively used for laser skin rejuvenation, both ablative and microablative. Despite seeming similarities in efficiency of their radiation’s absorption by soft tissues, these lasers may have completely different effects on skin: tissue vaporization with CO2 laser radiation always assumes existence of areas with irreversible thermal effects such as coagulation, dehydration, carbonization, and vaporization. If Er:YAG and vaporization is used for the same purpose, same thermal damage areas may be obtained but smaller in size. However, in case of sufficiently high energy density and short duration of pulses, an ablation mode may be implemented, in the case in which areas of irreversible thermal changes are contained within vaporization zone. Thus, underlying layers of irradiated tissue are not thermally damaged.
关键词： ablation mode,cavitation,Er:YAG laser,microablation,CO2 laser,skin rejuvenation,thermal damage
更新于2025-09-11 14:15:04
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Studies of the laser etching on painted plastic parts to prevent the risks of engraving failures at mechatronic devices
摘要： Nowadays, the automotive mechatronic devices are developed with many symbols engraved over the painted plastic parts. Many risks are coming due to painting layer, which could be dry or not, the paint thickness variability it is also one important aspect. The paper’s aim is to present the studies of the laser etching process and the risk reduction of the possible failure by using the 2D optical measurement of different parameters for the laser beam, also using the 3D scanning in order to see the deep etching of the paint. The experiments will let the team know what should be the parameter setting for the painted plastic materials delivered in production in different time after the painting, therefore to reduce the over-adjusting and first part approval process duration.
关键词： Nd:YAG laser,painted plastic parts,mechatronic devices,laser etching,automotive industry
更新于2025-09-11 14:15:04
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Er:YAG Laser and Cyclosporin A Effect on Cell Cycle Regulation of Human Gingival Fibroblast Cells
摘要： Introduction: Periodontitis is a set of inflammatory disorders characterized by periodontal attachment loss and alveolar bone resorption. Because of deficiency in periodontitis mechanical therapy, this study was aimed to explore the molecular influence of the erbium-doped: yttrium aluminum garnet (Er:YAG) laser and cyclosporin A (CsA) on human gingival fibroblasts (HGFs) for improvement in periodontal diseases therapy. Methods: We focused on articles that studied the proteome profiles of HGFs after treatment with laser irradiation and application of CsA. The topological features of differentially expressed proteins were analyzed using Cytoscape Version 3.4.0 followed by module selection from the protein-protein interaction (PPI) network using Cluster ONE plugin. In addition, we performed gene ontology (GO) enrichment analysis for the densely connected region and key proteins in both PPI networks. Results: Analysis of PPI network of Er:YAG laser irradiation on HGFs lead to introducing YWHAZ, VCP, HNRNPU, YWHAE, UBA52, CLTC, FUS and IGHG1 as key proteins while similar analysis revealed that ACAT1, CTSD, ALDOA, ANXA2, PRDX1, LGALS3, ARHGDI and EEF1A1 are the crucial proteins related to the effect of drug. GO enrichment analysis of hub-bottleneck proteins of the 2 networks showed the different significant biological processes and cellular components. The functional enrichments of module of Er:YAG laser network are included as fatty acid transmembrane transport, cytokinesis, regulation of RNA splicing and asymmetric protein localization. There are not any significant clusters in network of HGF treated by CsA. Conclusion: The results indicate that there are 2 separate biomarker panels for the 2 treatment methods.
关键词： cyclosporin A (CsA),human fibroblast cell,Er:YAG laser,Protein-protein interaction (PPI) network analysis,Gene ontology
更新于2025-09-11 14:15:04
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Effect of tungsten carbide partial dissolution on the microstructure evolution of a laser clad surface
摘要： Laser surface modification has been a way to promote wear resistance in dies and molds application. Previously, researchers have succeeded in enhancing surface properties through laser surface modification. The addition of particles in laser cladding process enhanced the surface properties by strengthening the modified AISI H13 tool steel structure. Controlled parameter was laser power, pulse repetition frequency (PRF) and scanning speed with a range of 1.7–2.5 kW, 30–70 Hz and 10.5–24.5 mm s?1 respectively. The powder addition executed by a preplaced method. The grain size and hardness properties of treated samples were characterized using scanning electron microscope (SEM) and hardness Vickers indenter respectively. Surface roughness was characterized using roughness tester. From the findings, tungsten carbide (WC) particles were dissolved homogenously within refined substrate grain structure at higher laser energy. Higher laser scanning speed contributed in uniform particles distribution. The grain refinement with W element in modified layer resulted in maximum hardness of 660 HV. Rapid solidification during laser processing produced metastable phase formation grain refinement, and a higher fraction of grain boundary which resulted in grain boundary strengthening, grain refinement and metastable phase formation. In this paper laser cladding of AISI H13 tool steel with micron size WC particles addition for enhanced surface properties was investigated. These findings are important to design high precision modification of die surface for high temperature forming process.
关键词： Laser cladding,Nd:YAG laser,Grain refinement,Phase transformation,Carbide dissolution,Tungsten carbide particle
更新于2025-09-11 14:15:04
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Nd: YAG Pulsed Laser Dissimilar Welding of UNS S32750 Duplex with 316L Austenitic Stainless Steel
摘要： Duplex stainless steels (DSSs), a particular category of stainless steels, are employed in all kinds of industrial applications where excellent corrosion resistance and high strength are necessary. These good properties are provided by their biphasic microstructure, consisting of ferrite and austenite in almost equal volume fractions of phases. In the present work, Nd: YAG pulsed laser dissimilar welding of UNS S32750 super duplex stainless steel (SDSS) with 316L austenitic stainless steel (ASS), with di?erent heat inputs, was investigated. The results showed that the fusion zone microstructure observed consisted of a ferrite matrix with grain boundary austenite (GBA), Widmanst?tten austenite (WA) and intragranular austenite (IA), with the same proportion of ferrite and austenite phases. Changes in the heat input (between 45, 90 and 120 J/mm) did not signi?cantly a?ect the ferrite/austenite phase balance and the microhardness in the fusion zone.
关键词： Nd: YAG,microstructure,austenitic steel,microhardness,laser welding,dissimilar material,duplex steel
更新于2025-09-11 14:15:04
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Low-cost multimode diode-pumped Tm:YAG and Tm:LuAG lasers
摘要： We report a continuous-wave operation of Tm:YAG and Tm:LuAG lasers pumped with a low-cost, multimode AlGaAs laser diode. First, the lifetime and the absorbance behavior of 5 mm, 6% Tm 3+ -doped YAG and LuAG crystals were thoroughly investigated. A low-cost multimode 3W laser diode at 781 nm was then used as a pump source for the Tm 3+ -doped laser systems. Using three different output couplers, up to 636 mW of output power was obtained from Tm:YAG laser, with a slope efficiency of 29% at 2017 nm. The maximum output power was 637 mW in the Tm:LuAG laser, with a slope efficiency of 28% at 2023 nm. The lasing performances showed a decreasing slope efficiency with an increasing level of output coupling, which leads to a high upconversion. Furthermore, using a birefringent filter in the resonators, the laser outputs were tuned from 1942 to 2086 nm in the Tm:YAG resonator and from 1931 to 2107 nm in the Tm:LuAG case.
关键词： diode-pumped lasers,infrared lasers,Tm:LuAG laser,Tm:YAG laser,tunable lasers,solid-state lasers,Lasers
更新于2025-09-11 14:15:04
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Acid resistance enhancement of human tooth enamel surface by Nd:YAG laser and incorporating silver nanoparticles: in vitro study
摘要： Purpose This work was devoted to assess the use of Nd:YAG laser with and without nanosilver particles to enhance tooth resistance of dental enamel against carries. Method Forty-eight tooth samples were randomly divided into three main groups and received different treatments. Samples of group 1 were illuminated by a single pulse at different laser fluences, while those of group 2 received different number of laser pulses at fixed laser fluence, and finally the samples of group 3 received laser and colloidal silver nanoparticle treatments at different conditions. The samples were subjected to Vickers microhardness test, atomic force microscopy analysis, scanning electron microscopy observation, energy dispersive spectroscopy investigation, and demineralization and re-mineralization tests. Results Due to fast laser heating and quenching, a significant microhardness increase in the treated dental enamel samples was seen. This resulted in an improvement in the enamel resistance against acids because of the decrease in hydroxyapatite lattice stress and the reduction in enamel solubility. The addition of silver nanoparticles to the laser-treated enamel surface helped stabilize the granules of the enamel surface tissue under the effect of laser irradiation. The demineralization of laser-treated samples showed higher Ca/P ratios than control group, indicating a higher resistance against acids. Conclusion The combined laser illumination and the addition of silver nanoparticles lowered the tooth abrasion degree and increased tooth resistance to decay. The demineralized samples of all laser-treated samples had higher Ca/P ratios compared to the demineralized control sample. Laser energy has modified the Ca/P mineral ratio and forms steadier and lesser acid soluble compositions.
关键词： Nd:YAG laser,Tooth decay reduction,Demineralization rate,Dental enamel,Silver nanoparticles
更新于2025-09-11 14:15:04