Papers by Keyword: Photonic Crystal

Abstract: In this study, we investigate the sensitive photonic crystal sensor formed by the coupling between two photonic crystals containing a superconducting layer. We consider TE polarization and normal incidence for the analysis presented in this work. Our study shows that the cavity mode resulting from this coupling is strongly dependent on the temperature of the superconductor layer. The effect of the temperature of the superconducting layer and thicknesses on the quality factor is examined. The results show that the sensor superconducting structure gives a high quality factor. This structure can be used to realize a highly sensitive photonic crystal sensor.

Abstract: In this article, we propose a biosensor based on a hybrid photonic crystal, the studied system is a superlattice consisting of a periodic alternation of poly(methyl methacrylate) (PMMA) and silicon dioxide (SiO₂) layers. Our study demonstrates that breaking the periodicity of the superlattice enables the excitation of Bloch surface waves within the photonic bandgap. This feature, along with its experimental convenience, justifies our choice of this structure for designing a biosensor in the Kretschmann configuration. Furthermore, we also analyzed the effect of various parameters, such as the number of layer repetitions, the frequency of the light waves used, and the thickness of the defect layer, on the biosensor's performance, the optimal structure, MgF₂/(PMMA/SiO₂)₃/D, demonstrates excellent sensing performance, achieving an angular sensitivity of 74°/RIU and a high figure of merit (FOM) of 1495/RIU.

Abstract: Axion is the dark particle introduced to the quantum chromodynamics to solve the strong CP-problem. Because of its dark nature, there are many indirect evidences, but axion itself have not been registered till now. In the paper, we report the observation of dark axion-like particles formed by the polariton coupling in the resonant microcavity of a globular photonic crystal. To overcome the very small cross-section, we use the Bose-Einstein condensation of polaritons into the nearest-to-the-surface microcavity of an opal-like globular photonic crystal. This way, the synchronicity conditions are met and all polaritons have the same wavefunction to be coupled. Moreover, the giant density of states of a Bose-condensate makes polariton coupling not only allowed but stimulated. At the experiment, we observe “Light Shining through a Wall” Primakoff effect which proves dark particles. The additional spectral peak at the unitary polariton line of a maximal transparency of a crystal allows to differ bipolaritons from other particles. The results can be used not only to generate dark particles at a lab, but also to get a laboratory source of an optical-frequency gravitational waves.

Abstract: A facile approach of robust polymer-based two-dimensional (2D) colloidal crystal (CC) layers was presented. This technology enables the convenient fabrication of an anti-counterfeiting coating with a polymeric 2D CC, allowing the fast preparation of functional polymer photonic materials. Briefly, a 2D CC was prepared by self-assembly of polystyrene (PS) submicrospheres, which was then transferred to substrates by adhesive polymeric solution and cured to form a photonic film. Such photonic films strongly and angle dependently diffract visible light, and the high transparency of the photonic layers ensured the readout from the substrate. The PC layers can also prevent the re-write or re-print on the substrate, indicating the potential applications in colorful and anti-counterfeiting coating materials.

Abstract: A “smart” molecular imprinted photonic crystal (MIPC) sensor has been developed based on the combination of photonic crystal (PC) and molecular imprinting technique (MIT). It can give rise to readable optical signals and color changes upon sensing benzocaine with detection limit of 16.5 μg/ml. In fish sample detection, the developed MIPC sensor shows satisfied result accuracy with HPLC. With the advantage of satisfactory specificity, rapid responsiveness and excellent recoverability, this MIPC material shows great potential towards on-site screening and visual detection of trace benzocaine in real sample.

Abstract: We developed a one-pot method for the fabrication of hydrogel-based photonic crystal (PC) materials. An array of monodisperse colloids was self-assembled within a polymer solution, which generates a visible light diffractable photonic mixture. This mixture was molded and gelated into a hydrogel PC material by freeze-thaw treatment. Drug release as well as the structure colour changing properties of the PC hydrogels were discussed, and the experiment results revealed that our one-pot design and the associated modification approach has potential in efficient fabrication of PC materials.

Abstract: Titania and alumina photonic crystals were fabricated by using stereolithographic additive manufacturing to control electromagnetic waves in terahertz frequency. Micro ceramic patterns were designed spatially by graphic software. Photosensitive liquid resin with ceramic particles were spread onto a grass substrate by mechanical knife edge, and two dimensional (2D) images were drawn using fine pattern exposing to create a cross sectional solid layer. After stacking these layers, the obtained three dimensional (3D) structures of composite precursors are dewaxed and sintered.

Abstract: Photonic crystals are dielectric materials with different refractive index or permittivity periodically. Photonic crystals have widely application for future technology such as waveguide, optical transistor, cavity of laser and biosensor. Photonic crystals can be fabricated in three types i.e 1D, 2D and 3D structure. In this paper, we report the successful fabrication of 3D photonic crystal from polystyrene particles. The fabrication process began with the synthesis of polystyrene particles followed by deposition on glass and flexible substrate using self-assembly method. We obtained polystyrene monodispered particles which have a uniform shaped with diameter 320 nm. Self-assembly method resulted to the arrangement of polystyrene particles on glass and flexible substrate. Stop band which is related to its optical property are at wavelength of 721 nm and 631 nm for photonic crystal on glass and flexible substrate, respectively. We found that filling fraction of photonic crystal on flexible substrate is lower than that of glass substrate due to some defects.