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- 摘要
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- 实验方案
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A monolithic on-chip magneto-optical isolator with 3 dB insertion loss and 40 dB isolation ratio
摘要： On-chip optical isolators constitute an essential building block for photonic integrated circuits (PICs). Here we experimentally demonstrated a magneto-optical isolator monolithically integrated on silicon featuring 3 dB insertion loss and 40 dB isolation ratio, both of which represent significant improvements over state-of-the-art. The isolator is also fully passive and operates under a simple unidirectional magnetization scheme. Such superior performance is enabled through a three-way combination of a strip-loaded waveguide design, a compositionally optimized chalcogenide glass as the light guiding medium, and low-loss taper structures created via gray-scale lithographic processing. The device represents an important step towards a practical solution for on-chip isolation in PICs.
关键词： Integrated optics devices,Magneto-optical materials,Chalcogenide glass,Resonators,Grayscale-lithography,Isolators
更新于2025-09-23 15:21:21
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AIP Conference Proceedings [AIP Publishing LLC PROGRESS IN APPLIED MATHEMATICS IN SCIENCE AND ENGINEERING PROCEEDINGS - Bali, Indonesia (29 September–1 October 2015)] - Reflectance imaging by fiber bundle endoscope: Vertical reconstruction by multipositional illumination
摘要： Fiber bundles for imaging internal organs with minimum physical damage have been increasingly developed for both basic life sciences and clinical applications. Reflectance imaging is possible using fiber bundles for detecting the intrinsic optical contrast of blood vessels and tissue structure. The placement of an illumination source adjacent to imaging optics causes scattered light from deeper tissue layers to illuminate superficial tissues and results in a reflectance image. However, it does not have focal capacity and lacks depth resolution. In this study, we performed spatial analysis for the vertical reconstruction of in vivo tissues using a multipositional illumination scheme. The observed image corresponded to the “shadow” of a target object. When we manipulated the location of illumination, the shadow moved horizontally depending on the depth of the target. We used this horizontal displacement as a cue and successfully performed the vertical reconstruction of mouse brain blood vessels.
关键词： Fiber optics,Reflectance imaging,Endoscopy
更新于2025-09-23 15:21:21
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[IEEE 2018 Second International Conference on Electronics, Communication and Aerospace Technology (ICECA) - Coimbatore (2018.3.29-2018.3.31)] 2018 Second International Conference on Electronics, Communication and Aerospace Technology (ICECA) - FSO Link Performance Analysis with Different Modulation Techniques under Atmospheric Turbulence
摘要： Free space optics (FSO) has achieved prominence in extremely large bandwidth, unlicensed spectrum and low power secure transmission in the field of wireless communication. Despite the advantages, it is deeply impacted due to atmospheric turbulence and fog weather conditions. This paper considers different modulation schemes under the presence of atmospheric turbulence and fog conditions. The desired expression of bit error rate (BER) is obtained by modeling the turbulence as gamma-gamma distributed channel and under this channel condition, 16-PPM has provided better performance than other schemes. BER is considered for the channel performance evaluation. This analysis can help to adopt a modulation technique according to the channel condition.
关键词： Bit error rate (BER),gamma-gamma distribution,atmospheric turbulence,Free space optics (FSO),Meijer’s G function
更新于2025-09-23 15:21:21
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Recent progress in all-fiber non-Gaussian optical beam shaping technologies
摘要： Rapid development of fiber lasers are being followed by wide ranges of applications in laser processing technologies. One of the key parameters to determine the laser-matter interaction is beam shape and there have been intense research activities on beam shaping using bulk-optics. However, fiber optic solutions would take clear advantages over bulk-optics especially for fiber laser sources in terms of the beam conversion efficiency, the throughput power, and the compact footprint. In this article, all-fiber optical beam shaping technologies are reviewed and they are categorized as the phase front modification on the fiber facet, the surface plasmonics on fiber, all-fiber Fourier transformation, and multimode interference. Their physical principles, beam shaping capability, and some of the novel applications are explained
关键词： Phase front engineering,Laser beam,Surface plasmon polariton,Beam Shaping,Multimode Interference,Fourier Transform,Fiber Optics,Single mode optical fiber
更新于2025-09-23 15:21:21
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Large diameter fiber-optics tweezers for Escherichia coli bacteria manipulation
摘要： Large diameter ?ber-optics tweezers are proposed in this paper, and their ability to trap and deliver Escherichia coli (E. coli) bacteria was characterized. The tweezers were formed by tapering four-mode ?ber (FMF) with 8.7 μm diameter, allowing the resonance ?eld of the extended high-order modes to be used for manipulating the micro-objects. The diameter of the FMF taper was much larger than that of reported ?ber-optic devices with nanoscale diameter, thereby making the device work as sturdier tweezers. The key factor for success is that, along the light transmission axis, the higher order modes have a unique mode ?eld that extends longer and with a larger range around the ?ber waist than the fundamental mode. At wavelengths ranging from 1500 to 1600 nm, especially close to 1560 nm, trapping and delivering of E. coli along the ?ber was observed. In addition, a further demonstration for operation time shows a larger tapered ?ber diameter was able to extend the service life of tweezers. The higher order micro-?ber modes offer a new opportunity for optical manipulation at the single-cell level.
关键词： Biophotonics,?ber-optics tweezers,optical ?bers
更新于2025-09-23 15:21:21
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On Geometric Optics over a Spherical Earth With an Exponential Refraction Index
摘要： The ray based method of geometrical optics can be used for wave propagation a over spherical earth with good results. A previous such a method also includes an exponential refraction index. This method gives good results for large terminal heights and distances, but for small distances, it has some shortcomings. In this paper, an improvement is proposed which remove these shortcomings. Also, as the method depends on numerical procedures, some improved numerical calculations are put forward.
关键词： refraction,geometrical optics,Electromagnetic propagation
更新于2025-09-23 15:21:21
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IEEE Access Special Section Editorial: Optical Wireless Technologies for 5G Communications and Beyond
摘要： Wide bandwidth and dense spatial reuse are of extreme importance for future wireless communication networks, including 5G and beyond. In particular, these properties are important to enable future wireless networks to cope with the explosive increase in the demand for high data-rate communications. Optical wireless communications (OWC) is a promising technology for achieving this goal due to the abundant reusable license-free optical spectrum. This potential of OWC attracted significant global attention both from communications and optoelectronics viewpoints, and continues to do so.
关键词： 5G,beam-steering,mixed FSO/fiber backhauling,OFDM,MIMO,Optical wireless communications,vehicle-to-vehicle communications,free-space optics,vehicle-to-infrastructure communications,network-layer aspects,visible-light communications
更新于2025-09-23 15:21:21
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Electromagnetic Modeling of Ships in Maritime Scenarios: Geometrical Optics Approximation
摘要： Global Navigation Satellite System-Reflectometry (GNSS-R), is succesfully employed for ocean altimetric and scatterometric applications. Recently, it has been suggested that GNSS-R can also be used for ship detection applications. To this purpose, an accurate electromagnetic modeling of the bistatic radar cross section of a ship lying over the sea surface would be very helpful. However, existing models are typically limited to monostatic configurations, thus restricting their applicability in multistatic scenarios, such as GNSS-R systems. In this work, we show a procedure to determine the bistatic radar cross section of a ship target, under the geometrical optics approximation. Numerical results show the impact of the geometry of acquisition and polarization on the bistatic radar cross section.
关键词： geometrical optics,radar cross section,Electromagnetic scattering,ship detection
更新于2025-09-23 15:21:21
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Recent Advances in Brillouin Optical Correlation-Domain Reflectometry
摘要： Distributed ?ber-optic sensing based on Brillouin scattering has been extensively studied and many con?gurations have been developed so far. In this paper, we review the recent advances in Brillouin optical correlation-domain re?ectometry (BOCDR), which is known as a unique technique with intrinsic single-end accessibility, high spatial resolution, and cost ef?ciency. We brie?y discuss the advantages and disadvantages of BOCDR over other Brillouin-based distributed sensing techniques, and present the fundamental principle and properties of BOCDR with some special schemes for enhancing the performance. We also describe the recent development of a high-speed con?guration of BOCDR (slope-assisted BOCDR), which offers a beyond-nominal-resolution detectability. The paper is summarized with some future prospects.
关键词： Brillouin scattering,optical fiber sensing,temperature sensing,distributed sensing,structural health monitoring,optical correlation-domain reflectometry,strain sensing,nonlinear optics
更新于2025-09-23 15:21:21
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Muscle oxygenation dynamics in response to electrical stimulation as measured with near-infrared spectroscopy: A pilot study
摘要： Neuromuscular electrical stimulation (NMES) is used for preventing muscle atrophy and improving muscle strength in patients and healthy people. However, the current intensity of NMES is usually set at a level that causes the stimulated muscles to contract. This typically causes pain. Quantifying the instantaneous changes in muscle microcirculation and metabolism during NMES before muscle contraction occurs is crucial, because it enables the current intensity to be optimally tuned, thereby reducing the NMES-induced muscle pain and fatigue. We applied near-infrared spectroscopy (NIRS) to measure instantaneous and deoxygenation changes in 43 healthy young adults during NMES at 10, 15, 20, 25, 30, and 35 mA. Having been stabilized at the NIRS signal baseline, total hemoglobin concentration increased immediately after stimulation in a dose-dependent manner (p < 0.05) until stimulation was stopped at the level causing muscle contraction without pain. Tissue deoxygenation appeared relatively unchanged during NMES. We conclude that NIRS can be used to determine the optimal NMES current intensity by monitoring oxygenation changes.
关键词： Muscle oxygenation dynamics,near-infrared spectroscopy,tissue optics,neuromuscular electrical stimulation
更新于2025-09-23 15:21:21