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Thermal darkening of one-dimensional photonic crystal containing tellurium suboxide
摘要： The purpose of this study is to experimentally and theoretically evaluate the optical properties of a one-dimensional photonic crystal (PC) with a defect layer before and after an annealing procedure. A sputtering technique with high index (TeOx) and low index (SiO2) materials was used to fabricate the 1D PC with a defect layer. The chemical and structural analysis of a single layer TeOx thin film was evaluated by X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDX), and X-Ray Diffraction (XRD). The optical constant of the single layer was also determined based on the envelope method from transmittance spectra measured by ultraviolet visible near-infrared spectrophotometry (UV-VIS-NIR). The measured reflectance spectra of the 1D PC were compared with the results simulated using the transfer matrix method (TMM) before and after the annealing procedure. A photonic bandgap (PBG) appears within the desired, near-infrared (NIR), region. The defect mode in the 1D PC was observed at λ = 1455 nm within the PBG of λ = 1235–1723 nm (Δλ = 488 nm). The reflectance spectra overall shifted toward longer wavelength due to thermal darkening effect resulting from the thermally induced optical property changes.
关键词： Photonic band gap,One-dimensional photonic crystals,Tellurium suboxide,Thermal darkening,Defect layer
更新于2025-09-23 15:21:01
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Efficient Low-Cost All-Flexible Microcavity Semitransparent Polymer Solar Cells Enabled by Polymer Flexible One-Dimensional Photonic Crystals
摘要： High-efficiency low-cost all-flexible microcavity semitransparent polymer solar cells (STPSCs) are comparatively studied in both fullerene- and nonfullerene-based systems with the structure strategy employing polymer flexible one-dimensional photonic crystals (F-1DPCs), as well as ITO-free UV/ozone plasma-treated polymer/ultrathin metal and PEDOT:PSS transparent electrodes. Based on the reasonable optimization of electrical and optical characteristics in device, the maximum power conversion efficiency with the use of polymer F-1DPCs can be greatly improved by 24~27% compared to the respective control devices. The improvement in JSC is comprehensively discussed, which is mainly ascribed to the enhancement of effective photon absorption in device. Although color tunability of fullerene and nonfullerene all-flexible STPSCs can be easily achieved with the use of different photonic bandgaps of polymer F-1DPCs, the CIE coordinates of nonfullerene STPSCs differ a lot from the original light source compared to the fullerene ones due to a high absorption coefficient in a narrow wavelength region. This work presents an easy and effective microcavity device strategy incorporated with different elements and demonstrates a new sketch of structure-absorption-performance relationships for fullerene- versus nonfullerene-based all-flexible STPSCs, which is compatible with low-cost roll-to-roll manufacturing and surely has a diversity of potential applications to better meet specific needs.
关键词： all-flexible,polymer solar cell,semitransparent,polymer flexible one-dimensional photonic crystals,microcavity
更新于2025-09-19 17:13:59
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Anisotropic Fluorescence Emission at the Surface of 1D-Photonic Crystal Biochips
摘要： Novel disposable optical biochips based on one-dimensional photonic crystals (1DPC) sustaining Bloch surface waves (BSW) are a desirable tool for the detection of several disease-related biomarkers. In particular, cancer biomarkers have gained considerable attention, due to the increasing demand for cancer treatment. Within this framework, the herein proposed optical biochips can quantify low concentration (sub ng/mL) of the ERBB2 breast cancer biomarker in biological complex matrices. To discriminate ERBB2 levels in several different cell lysate samples, we made use of a biosensing platform based on 1DPC biochips and on a reading instrument that can work in both a label-free and a fluorescence detection mode. Such combined configuration provides the advantage of complementary information and lower limit of detection (LoD) in the fluorescence mode [1]. In the label-free configuration the BSW excitation is achieved by a prism coupling system (Kretschmann-Raether configuration), like in the surface plasmon resonance (SPR) technique, resulting in a dip in the angular reflectance spectrum, shifting its position due to the refractive index changes [2]. The fluorescence mode is carried out by making use of dye labeled antibodies bound at the 1DPC surface. Coupling between the dye labels and a BSW results in strongly directional fluorescence emission. The advantages brought by the 1DPC, when compared to metal structures, are smaller energy dissipation and narrower resonances [3]. Presently, there is no study about photobleaching in experiments with BSW sustained by 1DPC, while it is evident that such phenomenon cannot be neglected in biosensing assays carried out close to the LoD, where quantitative and accurate information is needed. Here we report for the first time on cancer detection assays carried out with our platform, in which the trustworthiness of the output is put in doubt by photobleaching, which not only affects the overall emission intensity but also its polarization distribution via the TE and TM BSW modes provided by the 1DPC. The experimental data is interpreted by means of a theoretical model for the orientational distribution of dye labels over time, taking into account the density of the optical states of the 1DPC, photobleaching and rotational diffusion of surface bound emitters. The approach permits to model anisotropic fluorescence emission and to manage photobleaching effects in biosensing assays, leading to their correct interpretation.
关键词： one-dimensional photonic crystals,optical biochips,Bloch surface waves,cancer biomarkers,fluorescence emission,photobleaching
更新于2025-09-12 10:27:22
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Visualized Detection of Polyelectrolytes via 1D Photonic Crystals
摘要： The organic/inorganic hybrid 1D photonic crystal is applied for visible and label-free detection of charged substances. Exposure to aqueous solutions of various polyelectrolytes alters the swelling ratios of quaternized polymer layers due to the ionic interaction. Visible detection is thus attained along with a shift of the photonic stop band. Especially, by virtue of the diverse degrees and speeds of the shift, polyanions with different concentrations and molecular weights can be differentiated. Likewise, natural polyelectrolytes, such as proteins, have different solution pH values and isoelectric points. Thus, different charged properties yield three kinds of proteins that can be distinguished by the device via reflectance spectra. It is worth noting that biomarkers of illness with different concentrations can also be detected via the naked eye, without any labels. Fortunately, the detection sensitivity basically satisfies the usage requirement. Due to the convenience, flexibility, low power consumption and visibility, the label-free sensor is suitable for daily life.
关键词： one-dimensional photonic crystals,polyelectrolyte,isoelectric point,visualized detection,cancer marker
更新于2025-09-10 09:29:36
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DESIGNING PLANE WAVE MODULATORS USING 1DPC NANOSTRUCTURE WITH R-GRIN DEFECT LAYER
摘要： In this paper, we introduce plane wave modulators that are designed using one-dimensional photonic crystals (1DPC) containing radial gradient refractive index (r-GRIN) defect layers. Three kinds of r-GRIN materials with di?erent refractive index distribution functions are applied in numerical analysis. The properties of the phase and intensity of the transmitted plane wave beam through proposed structures are studied using the transfer matrix method. Radially-dependent defect modes, modulated phase and intensity are obtained according to the refractive index distribution functions. The results are predictable by regarding the Bragg condition and destructive interference, which are the origins of the photonic band gap (PBG). Due to the radial-dependency of the defect layer’s refractive index, the rays passing through di?erent transverse positions experience di?erent optical pathways. Therefore, the defect modes and transmitted spectrum (phase and amplitude) vary transversely. This study demonstrates another ability of the arti?cial PC structures to design plane wave modulators and manipulate its phase and intensity.
关键词： radial gradient refractive index,transfer matrix method,one-dimensional photonic crystals,plane wave modulators,photonic band gap
更新于2025-09-04 15:30:14
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Redshift gaps in one-dimensional photonic crystals containing hyperbolic metamaterials
摘要： In conventional all-dielectric one-dimensional photonic crystals (1DPCs), photonic gaps will shift toward short wavelengths (blueshift) as the incident angle increases for both transverse magnetic (TM) and transverse electric (TE) polarizations. We theoretically and experimentally achieve redshift gaps in 1DPCs composed of alternative hyperbolic metamaterials (HMMs) and dielectrics for TM polarization based on the anomalous wavevector dispersion of HMMs. The HMM is mimicked by layered titanium dioxide and silver with a subwavelength unit cell. However, the gaps remain to be blue-shifted for TE polarization. Therefore, the edges of such gaps can be utilized for high-e?ciency wide-angle polarization selection. We achieve e?cient polarization selection for incident angles ranging from 50 o to 80o at the wavelength of 365 nm.
关键词： one-dimensional photonic crystals,redshift gaps,polarization selection,hyperbolic metamaterials
更新于2025-09-04 15:30:14