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[IEEE 2018 Asia Communications and Photonics Conference (ACP) - Hangzhou, China (2018.10.26-2018.10.29)] 2018 Asia Communications and Photonics Conference (ACP) - Visible Coherent Femtosecond Supercontinuum from Air-Suspended-Core Photonic Crystal Fiber
摘要： We report efficient visible supercontinuum (SC) generated from a borosilicate glass photonic crystal fiber, using an 800-nm Ti:sapphire femtosecond laser. Using Michelson interferometer, the SC coherence has been measured to be ~0.8.
关键词： Fiber design and fabrication,Supercontinuum generation,Photonic crystal fibers
更新于2025-11-28 14:23:57
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A flexible surface-enhanced Raman substrates based on cellulose photonic crystal/Ag-nanoparticles composite
摘要： Surface-enhanced Raman scattering (SERS) significantly increases Raman scattering intensity. SERS usually uses rough-surface nano-metal materials such as gold, silver and copper as a substrate [1]. It has been widely used in surface science, analytical science and other fields [2-4]. According to the preparation method, SERS substrates can be divided into three categories: (1) solid phase substrates with fixed metal nanoparticles [5, 6]; (2) metal nanostructures prepared by nanoimprinting [7, 8]; (3) metal nanostructures prepared by template method [9-11]. Conventional SERS substrates, such as roughened surfaces of noble metals, are difficult to control and the SERS effect is unstable due to the random distribution of nanostructures. The microstructure of the nanometer regular pattern, which is processed by etching and electron beam deposition, is limited by the high cost of the instrument, the complicated production process, the difficulty to make large area and the subsequent modification of the surface. The SERS substrate prepared by a template of nanospheres array has a good controllability and reproducibility. By assembling nanospheres with different sizes to prepare the templates of different thicknesses, 2D metal films with different spacing can be obtained. The preparation of SERS substrate based on nanospheres array is simple and has low cost, easy regulation and high reproducibility. Protective agent and surfactant are not required in the preparation, meanwhile, the obtained substrate is relatively pure. PhCs are periodic structures which can be generated by a controllable self-assembly method of the spherical colloidal particles [12-15]. Light propagated inside PhCs follows Bragg's law of diffraction [16-19]. The characteristics of PhCs strongly depend on the spatial structure. Because of its cost-efficiency and easy preparation, PhC has attracted significant attentions in the application of optical sensors, optical switches [20, 21] and display devices [22-26]. The regular periodical structures can also be used as template to prepare other structural functional materials [27]. A lot of researches on the preparation and application of PhCs have been carried out in our recent work [28, 29]. Based on the special capture effect of PhC optical bandgap, the plasma effect of silver nanoparticles and the enrichment of cellulose matrix on analytes in organic solvents, we designed a combination of three properties for enhancing Raman scattering. Design concept is as follows: a PhC array which bandgap matches the incident light is used as a template, filled with a cellulose matrix that is easily degraded, and modified with silver nanoparticles. Based on the above design, a novel surface-enhanced Raman scattering substrate made by Ag-nanoparticles modified flexible cellulose photonic crystal film was firstly prepared. We synthesized an Ag-nanoparticles modified PhCs methylcellulose film (Ag-PHC-MCF) and carboxymethyl cellulose film (Ag-PHC-CMCF) SERS flexible substrates using the PhCs as templates. The innovative combination of metal nanoparticles and the ordered PhCs cellulose film (PHCCF) effectively avoided the aggregation of metal nanoparticles, as a result, the hot spots of the metal nanoparticles were distributed around the pores to ensure the uniform adsorption of the target analytes and uniform Raman signals on a large area. Through the excellent enrichment of cellulose film with pore structures, the targets in the organic solvent were captured on the cellulose film, so the Raman detection signals of the analyte were enhanced with the contact probability between the targets and the hot spots of metal nanoparticles increasing. At the same time, the light scattered on the PHCCF was enhanced significantly because of the trapping effect of PhC. Based on the original combination of the enrichment of porous methylcellulose, the plasmon resonance of Ag and the bandgap of photonic crystal, the composite film has a significant enhancement of the Raman signals. Simultaneously, due to its good degradability, it also has outstanding advantages in environmental protection. Meanwhile, it is easy to be carried and preserved because of its flexibility and light texture, which has great superiorities in transportation and storage.Therefore, it is of great significance in industrial pollutant detection or national defense safety monitoring.
关键词： SERS,cellulose films,photonic crystal,plasmonic responses
更新于2025-11-14 15:27:09
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Rapid detection of sulfaguanidine in fish by using a photonic crystal molecularly imprinted polymer
摘要： A photonic crystal (PC) sensor was prepared through molecular imprinting by using dispersed SiO2 microspheres as PC, sulfaguanidine (SG) as template, methacrylic acid as monomer, and ethylene glycol dimethacrylate as crosslinker. The preparation conditions were optimized as follows: molar ratio of template, monomer, and crosslinker was 1:10:4; pH was 6.0 in phosphate buffer; and volume fraction of methanol was 15%. The relationship between wavelength shift of reflection peak and SG concentration was found as: △λ=7.8887 lg(C)+79.9664. The response time was only 5 min. The limit of detection was 2.8×10-10 mol L-1. The sensor exhibited higher specificity for SG than its sulfonamide analogs. The sensor maintained original sensing performance after five cycles of usage. The recoveries of SG ranged from 93.8% to 111.2% in lake water and from 88.5% to 115.2% in fish samples. This finding suggested that the sensor can be used in food samples with complicated matrix.
关键词： Sulfaguanidine,Sensor,Photonic crystal,Molecular imprinting
更新于2025-09-23 15:23:52
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Dispersion flattened extremely high-birefringent kagome lattice elliptic core photonic crystal fiber in THz regime
摘要： A highly birefringent elliptic porous-core photonic crystal fiber with kagome lattice cladding has been presented for terahertz (THz) wave transmission. The slotted airholes inside the elliptic core effectively disrupt the symmetry of the porous-core which offers extremely high modal birefringence whereas the kagome cladding structure results in significantly low effective material loss (EML). The birefringence of the proposed structure is 9.73 × 10?2 for y-polarized mode at an operating frequency of 1 THz. The suggested structure also provides very flat dispersion over a bandwidth of 300 GHz. It is highly expected that this elliptic core waveguide would be remarkably useful in numerous polarization maintaining THz applications.
关键词： Photonic crystal fibers,Microstructured fibers,Fibres, polarization-maintaining,Optical communications,Fiber design and fabrication
更新于2025-09-23 15:23:52
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Bound states in the continuum in the double-period rectangular hole arrays perforated in one layer of photonic crystal slab in the visible wavelength region
摘要： We investigate optical bound states in the continuum (BICs) supported by a photonic crystal (PhC) slab penetrated with two periodic rectangular hole arrays embedded each other parallelly and vertically. It proves that the tunable off-Γ BICs can be found in the structure of both types, but the at-Γ BICs can only be obtained in the parallel structure. Quality factors (Q-factor) are obtained extremely high exceeding 105 for both types of structures. The tunable off-Γ BICs can be modulated by the structure parameters. Especially, the sensitivity of the resonant wavelength on the surrounding medium refractive index change is very large for the structure in both types, and tunable off-Γ BICs can be tuned by varying the environmental index. The results above accord well from the finite difference time domain method (FDTD) and the temporal coupled mode theory (CMT), which are beneficial to design practical resonance elements based on optical BICs in various new optical applications.
关键词： Double-periodic rectangular hole arrays,Photonic crystal,Fano resonance,Bound state in the continuum
更新于2025-09-23 15:23:52
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Preparation and optical properties of angle-dependent photonic crystals based on multi-layer films
摘要： The CreSiO2 photonic crystals, featured with two-dimensional structure and optical variation, was prepared by magnetron sputtering and electron beam lithography method. The finite difference time domain method (FDTD) is used to study the light-modulated characteristics of photonic crystals. Hue difference (⊿H) was used to evaluate the optical variations of photonic crystals, and bigger ⊿H indicates stronger angle dependency of color variation. Various parameters are analyzed for their impact upon ⊿H, including hole geometry (radium, r), hole gap (distance between the centers of two circles, d) and hole depth (h). The results matched the ones from simulation. Carbon quantum dots and up-conversion nanocrystals NaYF4 were inserted into the photonic crystals, and testing results of these doped crystals showed optical variation of fluorescence in the UV and IR region.
关键词： Finite difference time domain,Multi-layer films,Photonic crystal,Optical variability
更新于2025-09-23 15:23:52
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Ultrahigh- <i>Q</i> Photonic Nanocavity Devices on a Dual Thickness SOI Substrate Operating at Both 1.31- and 1.55-μm Telecommunication Wavelength Bands
摘要： A feasible method for integrating several silicon (Si) photonic devices with operating wavelengths separated by several hundred nanometers on a single chip will greatly help increasing capacities of small optical communication modules. This work demonstrates the integration of two photonic crystal nanocavity devices that exhibit ultrahigh quality factors (Q) and operate at the 1.31- and 1.55-μm bands. A dual thickness Si-on-insulator substrate forms the base of the device. The two nanocavity patterns are defined by electron beam lithography on the thick and thin substrate regions and are transferred to the top Si layer by performing plasma etching only once. All dimensions of the fabricated 1.31-μm nanocavity are (cid:2)15.5% smaller (1–1.31/1.55) than those of the 1.55-μm nanocavity; that is, they can be treated with the same photonic band diagram. Both nanocavities exhibit an ultrahigh Q > 2.0 × 106 and enable fabrication of nanocavity-based Raman lasers for the 1.31/1.55-μm bands with sub-microwatt threshold.
关键词： nanofabrication,microcavity,Raman Si laser,photonic crystal
更新于2025-09-23 15:23:52
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A nonlinear photonic crystal fiber for liquid sensing application with high birefringence and low confinement loss
摘要： This paper presents a nonlinear Photonic Crystal Fiber (PCF) based sensor to detect liquid analytes. An extensive analysis has been presented at wide range of wavelength (0.6 μm?1.6 μm) in order to investigate the impact of some design parameters. The numerical investigation has been done using the full vector Finite Element Method (FEM). The proposed model provides an outstanding nonlinear coefficient value with high birefringence, high sensitivity, and low confinement loss. The designed model can be used in sensing and bio-sensing research and their applications.
关键词： Effective Area,Sensitivity,Nonlinearity,Confinement loss,Photonic Crystal Fiber,Birefringence
更新于2025-09-23 15:23:52
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Highly sensitive strain sensor based on a novel Mach–Zehnder mode interferometer with TCF-PCF-TCF structure
摘要： We have demonstrated a high-sensitivity strain sensor based on a novel photonic crystal fiber (PCF) interferometer by means of splicing two sections of thin core fibers (TCF) with a piece of PCF between two single mode fibers (SMFs). The proposed MZI has exhibited an excellent fringe visibility as high as 21 dB in air. Particularly, the measurement range was up to 4 m ε and a strain sensitivity of ?1.89 pm/με was achieved. It was found that the strain sensitivity of the MZI was weekly dependent on the PCF length. The measured sensitivities of the MZI with 25 mm, 30 mm and 35 mm PCF at ～1590 nm were ?1.83 pm/με, ?1.85 pm/με and ?1.77 pm/με, respectively. Moreover, the temperature characteristics of the sensor were also investigated. Additionally, the sensor has advantages of simplicity of fabrication, low cost, compact size as well as large strain measurement range.
关键词： Strain sensor,Mach–Zehnder interferometer (MZI),Photonic crystal fiber (PCF),Thin core fiber (TCF)
更新于2025-09-23 15:23:52
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Photonic Crystal Fibres PCF for Different Sensors in Review
摘要： In this work, we present the update results for using the PCF as a sensors application, where we have chosen a modern collection of manuscripts previously published in scientific journals in the field of optical, biological and chemical sensors. So we compared their presented results, in order to reach the best results previously published in the use PCF for optical, biological and chemical sensors.
关键词： PCF,Sensors,Refractive Index Sensors,Photonic Crystal Fiber,Gass Sensors
更新于2025-09-23 15:23:52