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Investigations on the quantum chemical studies and physico-chemical properties of an opto-electronic material 1-Allyl-2-Aminopyridine-1-ium bromide
摘要： In the present work, the dual approach of quantum chemical studies and experimental characterizations of the title compound 1-Allyl-2-Aminopyridine-1-ium bromide (1A2APB) were carried out for the first time. The molecular geometry of 1A2APB was optimized by density functional theory (DFT) using B3LYP/6-311++G (d,p) basis set. The optimized geometric structural parameters were compared with the experimental findings and discussed. The dipole moment (μ) and first hyperpolarizability (β) were calculated to predict the NLO behavior. The frontier molecular orbital (FMO), molecular electrostatic potential (MESP), Mulliken atomic charge and thermodynamic properties were investigated to get a better insight of the molecular properties. Stability of the compound arising from hyper-conjugative interactions, intra-molecule re-hybridization and charge delocalization within the molecule were analyzed using NBO analysis. Further, 1A2APB was synthesized and good quality single crystals were grown by slow evaporation technique. Studies such as microanalysis and powder XRD were performed to ascertain material composition and phase respectively. The various characteristic functional groups were identified through FT-IR spectroscopic analyses. The NLO efficiency was measured to be about greater than 5 times that of standard KDP. Thermal behaviors were explored by the simultaneous TG/DTA-DSC thermograms. The UV–Vis–NIR spectral data and fluorescence spectrum were recorded to explore the optical transmission and emission properties respectively. The dielectric properties were evaluated as a function of frequency at various temperatures. The photoconducting nature was analyzed through photoconductivity measurement. The Vicker’s microhardness test was performed at room temperature from which the mechanical stability was analyzed through the classical Meyer’s relation.
关键词： Photoconductivity,Powder XRD analysis,DFT calculations,Organic materials,Non-linear optics,Crystal growth
更新于2025-09-23 15:23:52
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Observation the Multi-Soliton Patterns From the Er-Doped Mode-Locked Fiber Laser Modulated by PtSe2
摘要： The passively mode-locked ?ber laser modulated by low-dimensional materials can provide an ideal platform to investigate the soliton dynamics. Here, we experimentally explored the soliton formation and evolution from an erbium-doped ?ber laser mode-locked by mechanically exfoliated PtSe2 saturable absorber via evanescent ?eld interaction. With the increasing pump power, different soliton patterns, such as single soliton, two solitons, and bound soliton, can be observed experimentally. The experimental results can identify the non-linear optical response of the PtSe2 and may make avenue toward unveiling the nature of the soliton dynamics in the ?ber laser system.
关键词： non-linear optics,soliton dynamics,?ber laser,mode-locking,saturable absorber
更新于2025-09-23 15:21:01
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Editorial: Lasers in Accelerator Science and Secondary Emission Light Source Technology
摘要： Unifying laser and accelerator physics holds great promise for the development of future particle accelerators, light sources, and other scienti?c instruments due to increasingly synergistic advances at the cross section between these two ?elds. Their combined action has recently ushered in advanced accelerator facilities around the world that have enabled unique scienti?c and technological breakthroughs: from advanced electron and ion sources for high-energy physics to the ultrabright x-ray pulses to study ultrafast phenomena at elemental spatio-temporal scales [1–4]. The progress of ultra-intense femtosecond lasers, now attaining multi PetaWatt peak power, has recently enabled the demonstration of GeV electron beams in centimeter scale plasma accelerating section [5, 6], with the recent world record reaching 8 GeV in 20 cm [7]. As for ultrafast x-ray science, in their relatively short time since their advent, x-ray free electron lasers [8, 9] (FEL) have demonstrated the capacity to answer grand fundamental questions in a diverse set of areas in physics, chemistry, and biology, such as revealing vibration coherence in molecules [10], molecular bond formation, charge migration, and dissociation dynamics [11, 12], or ultrafast isomerization in biomolecules [13, 14], among many others. Further advances in facilities—such as augmented brightness, attosecond duration, or seeded emission—are poised to creating new scienti?c frontiers in atomic-scale correlated systems and ultrahigh resolution inner shell spectroscopies.
关键词： free electron laser (FEL),ultrafast optics,X-ray emission,non-linear optics,laser accelerated particles,secondary emission and photoemission
更新于2025-09-16 10:30:52
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Femtosecond Laser Lift‐Off with Sub‐Band Gap Excitation for Production of Free‐Standing GaN LED Chips
摘要： A novel method for lifting-off GaN-based LED structures from sapphire substrates is demonstrated. In this approach, ultrashort (350 fs) green pulses are scanned across the sample backside to lift-off the LED, utilizing two-photon absorption at the GaN/sapphire interface. The corresponding fluence regime is carefully investigated. Stable emission properties after laser lift-off are proven by cathodoluminescense measurements.
关键词： GaN,light-emitting diode,femtosecond laser,non-linear optics,laser lift-off
更新于2025-09-11 14:15:04
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Splitting and Motions of Dissipative Soliton Resonance Pulses in Mode-Locked Fiber Lasers
摘要： We numerically investigated the splitting and motions of dissipative soliton resonance (DSR) pulses in an all-normal-dispersion Yb-doped ?ber laser mode-locked by a non-linear optical loop mirror. At certain values of the system parameters, the initial single Gaussian pulse can evolve into an unstable DSR pulse with several dark solitons inside. After collisions of dark solitons, a big intensity dip occurs at the center of the DSR pulse, leading to the splitting of the DSR pulse. After splitting, the peak-to-peak separation between two DSR pulses increases at ?rst and ?nally reaches a ?xed value of 193 ps, indicating a steady-state multipulse operation The relative motions of separated DSR pulse originate from the phase shift.
关键词： dissipative soliton resonance,pulse splitting,non-linear optics,?ber lasers,mode-locked lasers
更新于2025-09-11 14:15:04
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Study of Polymorphism of Borovanadate Glass of Sodium by Raman Spectroscopy Low Frequencies
摘要： Sodium tetraborate (100 – x)(Na2B4O7.10H2O) – xV2O5, (x = 0 to 20 mole %) has been elaborated by splat cooling technique. Raman Measurements on the doped and non polish samples reveal the presence of the of α-NaVO3 crystal on the superficial layer. After polishing, Raman spectra characteristic of glasses are obtained with two main bands located at 555 and 1097 cm-1 in the undoped glass and four bands at 241, 381, 776 and 938 cm-1 for the vanadium oxyde doped glasses. The volume devitrification of these glasses occurs at 750° C and the β-NaVO3 crystalline phase is identified by Raman scattering.
关键词： Non-linear optics,Oxide glasses,XRD,Raman scattering,DSC
更新于2025-09-09 09:28:46