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- 摘要
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- 实验方案
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Hybridizing graphene and photonic crystal fibre
摘要： While the ability to increase the light–matter interaction by depositing graphene inside the air holes of a long length of photonic crystal fibre is worth celebrating, cautious optimism is called for when we begin to discuss the industrialization of graphene-based fibre-optic components.
关键词： photonics,graphene,photonic crystal fibre,light–matter interaction
更新于2025-09-23 15:19:57
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Spectroscopic diagnostics of continuous and transient microplasma formed in a millimeter wave photonic crystal
摘要： We present spectroscopic measurements of a microplasma formed within a photonic crystal (PhC) at argon gas pressures up to 750 Torr. Continuous and pulsed millimeter waves (MMW) generate plasma at a vacancy defect within the crystal. Rotational gas temperatures of 300-1050 K and electron densities of 0.5-2×1020 m-3 are obtained from the CH rotational emission spectrum and from Stark broadening of the ???? atomic transition. Electron density is found to be weakly dependent on MMW power because the plasma expands within the defect volume at higher power. Pulsed MMWs slightly increase the peak electron density compared to continuous waves with the same peak power. With MMW pulses, a rapid decrease of wave transmission through the PhC is observed at the beginning of plasma formation. During plasma ignition two distinct plasmas are formed, one on the conducting wall of the PhC near the optical access port and a second within the center of the PhC defect. With longer periods between pulses, the weak wall plasma is observed to form before the principal plasma in the defect, which aids in initiating the main plasma.
关键词： photonic crystal,millimeter waves,electron density,spectroscopic diagnostics,microplasma,gas temperature
更新于2025-09-23 15:19:57
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Enhancement of magneto-optical properties in magnetic photonic crystal slab waveguide based on yttrium iron garnet
摘要： In this work, a polarization-independent waveguide based on magnetic photonic crystal (MPC) with a triangular lattice of air holes in Yttrium Iron Garnet (YIG) slab grown on alumina (Al2O3) substrate is proposed, where both TE-like and TM-like periodic band gaps overlap. YIG is well known for its attracting magneto-optical (MO) properties and used to produce a coupling between the TE and TM modes. Thus, a nonreciprocal effect can be obtained by applying an external magnetic field parallel to the direction of propagation. At 1550 nm, the complete photonic band gap is simulated and optimized using the three dimensional plane-wave expansion method. The aim of this study is to enhance Faraday rotation (FR) while maintaining a low modal birefringence. A numerical analysis in function of magnetic gyration (g) has been reported, using the BeamProp software. The results reveal a proportional relation between FR, ?n and g, such for g = 0.5, a large FR of 26.11×104 °/cm with ?n = 7×10–6. The results show a real improvement of this MPC structure based on YIG with larger FR, lower modal birefringence and minimal losses. The notable enhancement in the MO behaviour could improve the performance of optical isolators, and makes it suitable for nonreciprocal devices.
关键词： modal birefringence,magneto-optical properties,Yttrium Iron Garnet,Faraday rotation,magnetic photonic crystal
更新于2025-09-23 15:19:57
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A Sharply Bent Waveguide with a Microcavity Constructed by an Air-Bridge Type Two-Dimensional Photonic Crystal Slab
摘要： An e?cient sharply bent waveguide with a microcavity constructed by an air-bridge type two-dimensional photonic crystal slab is analyzed. The method of solution is the three-dimensional ?nite di?erence time domain (FD-TD) method. The bent waveguide has a microcavity structure that connects to an input and an output waveguide ports. The radius and position of air-holes surrounding the microcavity are modi?ed to adjust the resonant frequency to the single-mode regime of the waveguides. It is con?rmed that input optical power is transmitted e?ciently to the output waveguide due to resonant tunneling caused by the microcavity.
关键词： FD-TD method,bent waveguide,microcavity,photonic crystal waveguide
更新于2025-09-23 15:19:57
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Analysis of a Single Solid Core Flat Fiber Plasmonic Refractive Index Sensor
摘要： In this article, a single solid core flat fiber (SSCFF) refractive index sensor based on surface plasmon resonance (SPR) is proposed and analyzed numerically using the finite element method (FEM). The proposed flat fiber consists of a single array of five circular holes. Among them the central hole is made of GeO2-doped silica which is forming the core. Other holes are filled with air and situated symmetrically on both sides of the central solid core. The upper flat surface of the fiber is coated with a thin plasmonic gold layer which is protected by an active titanium dioxide layers. Analyte is situated on top of these layers. The wavelength interrogation technique is applied to study the coupling characteristics between the core-guided mode and the surface plasmon mode as well as for the refractive index measurement. Numerical analysis results show that this sensor is able to detect high refractive index analytes from 1.49 to 1.54 with a good linear response. Additionally, the dependence of surface plasmonic resonance wavelength on analyte refractive index is studied. The maximum wavelength sensitivity of this sensor is found to be 4782 nm/RIU with a high resolution of 2.09 × 10?5 RIU. The effects of different structural parameters on loss spectrum are studied in detail to optimize this SSCFF structure. In comparison to traditional PCF, this SSCFF structure is fabrication complexity free as well as a suitable candidate for developing portable devices and high refractive index analyte sensors, particularly chemical and protein sensors.
关键词： Photonic crystal fiber,Surface plasmon,Optical sensing,Finite element method,Refractive index sensor
更新于2025-09-23 15:19:57
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Photonic Crystal Circular Nanobeam Cavity Laser with Type-II GaSb/GaAs Quantum Rings as Gain Material
摘要： The optical emission from type-II semiconductor nanostructures is influenced by the long carrier lifetime and can exhibit remarkable thermal stability. in this study, utilizing a high quality photonic crystal circular nanobeam cavity with a high quality factor and a sub-micrometer mode volume, we demonstrated an ultra-compact semiconductor laser with type-ii gallium antimonide/gallium arsenide quantum rings (GaSb/GaAs QRs) as the gain medium. the lasing mode localized around the defect region of the nanobeam had a small modal volume and significant coupling with the photons emitted by QRs. it leads the remarkable shortening of carrier lifetime observed from the time-resolved photoluminescence (tRpL) and a high purcell factor. furthermore, a high characteristic temperature of 114 K was observed from the device. The lasing performances indicated the type-II QRs laser is suitable for applications of photonic integrated circuit and bio-detection applications.
关键词： gain material,laser,nanobeam cavity,type-II GaSb/GaAs Quantum Rings,photonic crystal
更新于2025-09-23 15:19:57
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Thermal design management of highly mechanically stable wavelength shifter using photonic crystal waveguide
摘要： A thermally tunable device based on photonic crystal waveguide integrated with the micro-hotplate on its surface is proposed. A design strategy for modelling of temperature and stress in the MHP is investigated for providing robustness and high mechanical stability in the reconfigurable device. The required temperature is obtained under stress elongation fatigue limit for thermal tuning applications in optical devices. The performance parameters like confinement factor, wavelength transfer coefficient and extinction ratio are obtained as 78.2%, 0.086 nm/K and 30.04 dB respectively with an excess loss of only 0.20 dB. The response-time in the optimized device is 12 μs for achieving the switching spectral shift of 26 nm in the transmission spectrum of PCW. The reconfigurable device platform offers a great potential for wide range of tuning in switches and filters applications
关键词： Thermally tunable device,Photonic crystal waveguide,Thermo-optic tuning,Mechanical stability,Micro-hotplate
更新于2025-09-23 15:19:57
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Helicity Enhanced Torsion Sensor Based on Liquid Filled Twisted Photonic Crystal Fibers
摘要： A highly sensitive torsion sensor can be constructed by combining a twisted photonic crystal fiber with a liquid-filled waveguide in its air-hole cladding. The torsion sensitivity of this type of sensor is determined directly by the phase-matching conditions between the fiber core mode and the liquid waveguide mode, which can be improved by tuning the helicity (denoted by the initial twist rate, α0) of the twisted photonic crystal fiber. The enhancement mechanism of α0 on the sensitivity of the proposed torsion sensor is investigated theoretically, followed by experimental verifications, and a torsion sensitivity as high as 446 nm·mm·rad?1 can be obtained by tailoring these parameters. Experimental results show that the torsion sensitivity increases with α0 decreasing from 3.142 to 3.925 rad/mm, which are in consistence with that of the numerical predictions. The demonstrated torsion sensor is expected to contribute to the development of highly sensitive torsion-related photonic crystal fiber devices.
关键词： photonic crystal fibers,microstructure fabrication,fiber optics sensors
更新于2025-09-23 15:19:57
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Observation of topologically enabled unidirectional guided resonances
摘要： Unidirectional radiation is important for various optoelectronic applications, such as lasers, grating couplers and optical antennas. However, almost all existing unidirectional emitters rely on the use of materials or structures that forbid outgoing waves—that is, mirrors, which are often bulky, lossy and difficult to fabricate. Here we theoretically propose and experimentally demonstrate a class of resonances in photonic crystal slabs that radiate only towards one side of the slab, with no mirror placed on the other side. These resonances, which we name ‘unidirectional guided resonances’, are found to be topological in nature: they emerge when a pair of half-integer topological charges in the polarization field bounce into each other in momentum space. We experimentally demonstrate unidirectional guided resonances in the telecommunication regime by achieving single-side radiative quality factors as high as 1.6 × 105. We further demonstrate their topological nature through far-field polarimetry measurements. Our work represents a characteristic example of applying topological principles to control optical fields and could lead to energy-efficient grating couplers and antennas for light detection and ranging.
关键词： Unidirectional radiation,Light detection and ranging,Photonic crystal slabs,Telecommunication regime,Grating couplers,Topological charges
更新于2025-09-23 15:19:57
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Theoretical Investigation of an Alcohol-Filled Tellurite Photonic Crystal Fiber Temperature Sensor Based on Four-Wave Mixing
摘要： For this study, a temperature sensor utilizing a novel tellurite photonic crystal fiber (PCF) is designed. In order to improve the sensor sensitivity, alcohol is filled in the air holes of the tellurite PCF. Based on the degenerate four-wave mixing theory, temperature sensing in the mid-infrared region (MIR) can be achieved by detecting the wavelength shift of signal waves and idler waves during variations in temperature. Simulation results show that at a pump wavelength of 3550 nm, the temperature sensitivity of this proposed sensor can be as high as 0.70 nm/°C. To the best of our knowledge, this is the first study to propose temperature sensing in the MIR by drawing on four-wave mixing (FWM) in a non-silica PCF.
关键词： mid-infrared region,tellurite photonic crystal fiber,four-wave mixing,temperature sensor
更新于2025-09-23 15:19:57