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Diode-pumped single-pass tunable mid-infrared gas Raman source by methane-filled hollow-core fiber
摘要： We report here, to the best of our knowledge, the first diode-pumped single-pass tunable mid-infrared fiber gas Raman laser source using methane-filled hollow-core fibers. Pumped by a homemade tunable high peak-power amplified diode laser, whose wavelength covers the range of 1540 nm to 1560 nm, the mid-infrared laser emission over the range of 2796 nm to 2863 nm is generated by the stimulated Raman scattering of methane molecules. The highest average output power of ~34 mW at 2829 nm is achieved with 14.2 m fiber at 16 bar when pumped at 1550 nm. This paper opens new opportunities for compact tunable mid-infrared fiber lasers.
关键词： gas lasers,Raman lasers,fibre lasers,stimulated Raman scattering
更新于2025-11-28 14:23:57
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Phonon coherences reveal the polaronic character of excitons in two-dimensional lead halide perovskites
摘要： Hybrid organic–inorganic semiconductors feature complex lattice dynamics due to the ionic character of the crystal and the softness arising from non-covalent bonds between molecular moieties and the inorganic network. Here we establish that such dynamic structural complexity in a prototypical two-dimensional lead iodide perovskite gives rise to the coexistence of diverse excitonic resonances, each with a distinct degree of polaronic character. By means of high-resolution resonant impulsive stimulated Raman spectroscopy, we identify vibrational wavepacket dynamics that evolve along different configurational coordinates for distinct excitons and photocarriers. Employing density functional theory calculations, we assign the observed coherent vibrational modes to various low-frequency (?50 cm?1) optical phonons involving motion in the lead iodide layers. We thus conclude that different excitons induce specific lattice reorganizations, which are signatures of polaronic binding. This insight into the energetic/configurational landscape involving globally neutral primary photoexcitations may be relevant to a broader class of emerging hybrid semiconductor materials.
关键词： resonant impulsive stimulated Raman spectroscopy,polaronic character,two-dimensional perovskites,density functional theory,excitons,phonon coherences
更新于2025-09-23 15:23:52
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Quantum-Classical Correspondence for Adiabatic Shortcut in Two- and Three-Level Atoms
摘要： The methods of quickly achieving the adiabatic effect through a non-adiabatic process has recently drawn widely attention both in quantum and classical regime. In this work ,we study the classical adiabatic shortcut for two- and three-Level atoms by transforming the quantum version into classical one via quantum-classical corresponding theory. The results shows that, the additional couplings between the oscillators can be used to speed up the adiabatic evolution of coupled oscillators. Furthermore, we find that the quantum-classical correspondence theory still holds for the couter-adiabatic driving Hamiltonian for the TQD. This means that, we can obtain the counter-adiabatic driving Hamiltonian for a classical system by averaging over its quantum correspondence in a quantum system. This provides a feasible way to study the classical adiabatic shortcut and the simulation for the quantum adiabatic shortcut in a classical system.
关键词： Stimulated Raman adiabatic passage,Quantum-classical correspondence,Adiabatic shortcut
更新于2025-09-23 15:23:52
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[IEEE 2018 20th International Conference on Transparent Optical Networks (ICTON) - Bucharest (2018.7.1-2018.7.5)] 2018 20th International Conference on Transparent Optical Networks (ICTON) - Towards Applications of Stimulated Raman Scattering in Nanophotonics
摘要： Nanophotonics is a rapidly evolving field, exploring behaviour of light on the micro/nano scale and the interaction of micro/nano objects with light. The driving force for its development is the promise to go far beyond the conventional boundaries of photonics. Because of the diffraction limit, high-density regular optical components do not have the ability to confine light down to the microscale dimension. The footprint of devices becomes more critical for applications with limited physical space, such as on-chip silicon-based photonic devices. In this paper, a review of some of the most significant accomplishments in the field of stimulated Raman scattering in microstructures is reported. These findings indicate promising perspectives for integrated Raman lasers.
关键词： Raman laser,stimulated Raman scattering,nanophotonics,nonlinear optics
更新于2025-09-23 15:22:29
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Estimation of Signal-to-Cross Talk Ratio of Stimulated-Raman-Scattering-Induced Cross Talk in Wavelength-Division-Multiplexing-Based Radio-over-Fiber Links
摘要： This paper evaluates the signal-to-cross talk ratio (SXR) of cross talk induced by stimulated Raman scattering (SRS) in radio-over-fiber (RoF) systems based on wavelength-division multiplexing. The reported study has modeled the relations of SXR to modulation frequency, optical power, transmission length, and effective area of fiber for various values of the walk-off parameter. The summary of experimental reveals that SXR decreases with increases in channel input power and transmission distance and increased with increases in fiber effective area and modulation frequency. Results showed that increasing the walk-off parameter from 13.6 to 81.6 ps/km increased the SXR by almost 6 dBm. Furthermore, various fibers, including standard single-mode fiber (SMF), Corning LEAF, and Alcatel TeraLight were tested for their capacity to mitigate SRS-induced cross talk. These tests demonstrated that standard SMF suppressed SRS cross talk effectively and offered values of SXR 3 dBm and 6 dBm higher than the values exhibited by Alcatel TeraLight and Corning LEAF, respectively.
关键词： wavelength-division multiplexing (WDM),signal-to-cross talk ratio (SXR),stimulated Raman scattering (SRS),single-mode fiber (SMF),radio over fiber (RoF)
更新于2025-09-23 15:22:29
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Integrable all-optical pass switch
摘要： A completely new design for an all-silicon all-optical pass switch has been proposed based on the stimulated Raman scattering (SRS) in silicon nanocrystal embedded slotted photonic crystal waveguide (SPCW). Substantial miniaturisation in the device footprint and operating power has been attained by merging the benefits of the giant SRS gain and the ultra-high optical confinement of the SPCW. The proposed switch offers a tremendously high contrast ratio of (cid:1) 27 dB between the logic levels and an extraordinary bit rate of 125 Gbps.
关键词： high bit rate,stimulated Raman scattering,high contrast ratio,slotted photonic crystal waveguide,silicon nanocrystal,all-optical pass switch
更新于2025-09-23 15:21:21
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Nonlinear Optics || Stimulated Raman Scattering and Stimulated Rayleigh-Wing Scattering
摘要： The spontaneous Raman effect was discovered by C.V. Raman in 1928. To observe this effect, a beam of light illuminates a material sample (which can be a solid, liquid, or gas), and the scattered light is observed spectroscopically. In general, the scattered light contains frequencies different from those of the excitation source. Those new components shifted to lower frequencies are called Stokes components, and those shifted to higher frequencies are called anti-Stokes components. The Stokes components are typically orders of magnitude more intense than the anti-Stokes components.
关键词： anti-Stokes components,spontaneous Raman scattering,stimulated Raman scattering,Raman effect,Stokes components
更新于2025-09-23 15:21:01
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Time-Resolved Impulsive Stimulated Raman Spectroscopy with Synchronized Triple Mode-Locked Lasers
摘要： A complete understanding of a photochemical reaction dynamics begins with real-time measurements of both electronic and vibrational structures of photoexcited molecules. Time-resolved impulsive stimulated Raman spectroscopy (TR-ISRS) with femtosecond actinic pump, Raman pump, and Raman probe pulses is one of the incisive techniques enabling one to investigate the structural changes of photoexcited molecules. Here, we demonstrate that such femtosecond TR-ISRS is feasible with synchronized triple mode-locked lasers without using any time-delay devices. Taking advantage of precise control of the three repetition rates independently, we could achieve automatic scanning of two delay times between the three pulses, which makes both rapid data acquisition and wide dynamic range measurement of the fifth-order TR-ISRS signal achievable. We thus anticipate that the present triple mode-locked laser-based TR-ISRS technique will be of critical use for long-term monitoring of photochemical reaction dynamics in condensed phases and biological systems.
关键词： pump-dump-probe,fifth-order electronic spectroscopy,impulsive stimulated Raman spectroscopy,femtosecond Raman scattering,Time-resolved vibrational spectroscopy
更新于2025-09-23 15:21:01
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Diode pumped Nd:YVO <sub/>4</sub> /LBO/Ba(NO <sub/>3</sub> ) <sub/>2</sub> Raman laser at 563 nm
摘要： Radiation at a wavelength of 563 nm was achieved using an all-solid-state laser system based on a diode-pumped actively Q-switched Nd3+:YVO4 laser with intra-cavity second harmonic generation in LBO followed by intra-cavity Raman conversion in Ba(NO3)2. The output power of 101 mW was achieved under a pump power of 5 W and a modulation frequency of 12.7 kHz with a slope conversion efficiency of 19%. The achieved peak power at 563 nm was 0.67 kW, which allows one to use this laser in medical treatment through selective excitation of deoxyhemoglobin into its long-wavelength absorption peak.
关键词： stimulated Raman scattering,intracavity second harmonic generation,563 nm,Raman laser
更新于2025-09-23 15:21:01
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Absolute stimulated Raman side scatter in direct-drive laser-produced plasmas
摘要： Production of suprathermal electrons by stimulated Raman scattering (SRS) is a principal concern for contemporary direct-drive inertial confinement fusion experiments at the National Ignition Facility and similar systems since such electrons penetrate and preheat the target core, preventing efficient implosion. The higher temperatures and longer scale lengths in these experiments favor SRS over two-plasmon decay, which predominated in earlier experiments. In particular, current experiments are expected to exceed the threshold for absolute Raman side scatter, which would then dominate the interaction since it grows temporally until saturated by nonlinear mechanisms such as hot-electron production. Until recently, analyses of SRS side scatter have treated the case of a single laser beam incident on a plasma, but the direct-drive approach to laser fusion employs a multitude of beams to drive the implosion. Here, we present an analysis that can be applied to an arbitrary number of beams with varied angles of incidence and polarizations. In the case of a single beam, it allows a physically motivated derivation and verification of an analytic threshold formula. In the general case of multiple beams and arbitrary orientation and polarizations, the threshold is found by numerical integration of a set of first-order linear partial differential equations.
关键词： direct-drive,stimulated Raman scattering,inertial confinement fusion,laser-produced plasmas,suprathermal electrons
更新于2025-09-23 15:21:01