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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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[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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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
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Direct mineralogical imaging of economic ore and rock samples with multi-modal nonlinear optical microscopy
摘要： Multi-modal nonlinear optical (NLO) microscopy, including stimulated Raman scattering (SRS) and second harmonic generation (SHG), was used to directly image mineralogical features of economic ore and rock samples. In SRS/SHG imaging, ore samples generally require minimal preparation and may be rapidly imaged, even in their wet state. 3D structural details, at submicron resolution, are revealed tens of microns deep within samples. Standard mineral imaging based on scanning electron microscopy (SEM), with elemental analysis via energy dispersive X-Ray spectroscopy, was used to independently validate the mineral composition of the samples. Spatially-resolved SRS from dominant Raman-resonant bands precisely maps the locations of specific minerals contained within the samples. SHG imaging reveals locally non-centrosymmetric structures, such as quartz grains. Competing absorption and nonlinear scattering processes, however, can reduce contrast in SRS imaging. Importantly, the correlation between standard electron microscopy and multi-modal NLO optical microscopy shows that the latter offers rapid image contrast based on the mineral content of the sample.
关键词： mineralogical imaging,second harmonic generation,stimulated Raman scattering,rock samples,nonlinear optical microscopy,economic ore
更新于2025-09-23 15:21:01
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The interaction of parametric instabilities from 3?? laser and 2?? laser in large-scale inhomogeneous plasmas
摘要： The interaction of parametric instabilities from 3ω laser and 2ω laser in large-scale inhomogeneous plasmas. The mechanism of energy transfer from 3ω pump light to stimulated Brillouin scattering (SBS) generated by 2ω pump light is proposed. The backscattering light of stimulated Raman scattering (SRS) generated by 3ω pump light can work as a seed of the SBS of 2ω pump light, which results in the increase of the later. Adding 2ω pump light into 3ω pump light will decrease the reflectivity of SBS generated from 3ω pump light. The total reflectivity will firstly decrease and then increase with increase of the ratio of 2ω light intensity to the intensity of 2ω and 3ω lights f = I2ω0/(I2ω0 + I3ω0), and will be controlled in a lower level when this ratio f is about 10% ? 20%. These results give a method to control the total reflectivity of SBS and SRS in inertial confinement fusion (ICF) by adding 2ω light into 3ω light.
关键词： inertial confinement fusion,2ω laser,3ω laser,parametric instabilities,stimulated Raman scattering,stimulated Brillouin scattering,large-scale inhomogeneous plasmas
更新于2025-09-23 15:19:57
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Calculation of Direct Drive Targets for Megajoule Laser Facilities with Radiation in the Second and Third Harmonics of Nd Laser
摘要： The numerical results for cryogenic direct drive targets of megajoule facilities with radiation in the second and third harmonics of a Nd laser are presented. The calculations were performed with the 1D radiation hydrodynamics code ERA with the laser light absorption model that takes into account stimulated Brillouin scattering (SBS), generation of fast electrons in the processes of two-plasmon decay (TPD), and stimulated Raman scattering (SRS). The verification of the developed models was carried out on the basis of the comparison with experiments performed at the OMEGA and NIF facilities. The ignition margin (WQ) of nonuniform fusion targets with an allowance for energy losses due to radiation transfer and heat conduction from the hot spot was the objective of the target optimization. The calculations showed that SBS and target heating by fast electrons generated in TPD and SRS fatally reduce WQ of targets with a CH ablator for the megajoule laser with wavelength λ = 0.53 μm. The possibilities of decreasing these effects by replacing a CH ablator with a glass ablator and reducing the laser intensity upon increasing the target aspect ratio are considered. However, in both cases, WQ remains substantially below unity for the laser with wavelength λ = 0.53 μm. The ignition margin increases by a factor of ~2 upon transition from the second to the third harmonic of a Nd laser. A glass ablator almost eliminates fast electrons in calculation with the laser wavelength λ = 0.35 μm. In this case, if SBS is reduced by a factor of 3–4 via shifting the laser emission lines in the neighboring channels by Δλ ≈ 10–20 ?, the ignition margin WQ ~ 2 and a fusion energy yield of ~50 MJ are obtained in the 1D calculation for a laser energy of ~2 MJ and the third harmonic of a Nd laser.
关键词： megajoule laser facilities,two-plasmon decay,fast electron generation,direct drive targets,stimulated Raman scattering,thermonuclear ignition margin of target,stimulated Brillouin scattering
更新于2025-09-23 15:19:57