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Radiation detection is being revolutionized by integrating photonic elements into scintillators. In this study, a scalable and cost‐effective method is proposed to achieve tuneable emission enhancement across the visible spectrum by colloidal self‐assembly of photonic crystals on scintillator surfaces. This concept is demonstrated for Eu3+/Tb3+‐doped Gd and Ta oxides. Widely available and affordable colloidal nanospheres of SiO2 or polymethyl methacrylate are self‐assembled on these scintillators. The size of the nanospheres is carefully optimized to match the desired emission lines of Eu3+/Tb3+. The result is homogeneous and closely‐packed structures with clear photonic bandgap in the visible range. Under X‐ray excitation, the scintillators covered with the photonic layers exhibit enhanced light extraction in the direction perpendicular to the surface, compared to isotropic emission in the bare scintillator. Such scintillation directionality, when optically matched with a proper detector, will result in higher efficiency of the overall detection system. Moreover, X‐ray imaging demonstrates an enhancement of 25% in system resolution of the scintillator supplemented with the photonic layer compared to unmodified scintillators. The proposed method is scintillator‐ and nanosphere‐agnostic, thus offering a promising versatile approach for directing the scintillation light toward a photodetector and increasing detection system performance, including high‐resolution imaging applications. [ABSTRACT FROM AUTHOR]

A one-dimensional magnetized InSb photonic crystals layered topology (PCLT) proposed in this paper can realize the functions of logic OR operation and magnetic field sensing. In the proposed PCLT, under the transverse magnetic polarization, the value and frequency of the absorption peak (AP) can be controlled by the external magnetic fields and has a high-quality factor (Q), thus OR logical operation can be achieved. Additionally, since InSb has a magneto-optical effect under magnetic fields, the parity of the structure of the PCLT which adds InSb as defect layers can be broken. Electromagnetic waves obtain nonreciprocity when propagating in opposite directions within the PCLT, which means that logical operation and magnetic field sensing based on AP can be obtained on the forward and backward scales. For the detection, on the forward scale, optimum performances of Q, sensitivity (S), the figure of merit, and detection limit are 62 372.09, 0.0169 (2 Ď€c / d) /T, 4225 Tâˆ'1, 1.2 Ă— 10âˆ'5 T, and for the backward detection, the corresponding values are 63 626.25, 0.0225 (2 Ď€c / d) /T, 5200 Tâˆ'1, 1 Ă— 10âˆ'5 T. The designed PCLT is innovative in multi-functional and multi-scale, having certain research value and prospects. [ABSTRACT FROM AUTHOR]

Holographic sensors are optical devices capable of tuning reflection wavelength, dependent upon nanostructured variations in refractive index. Computational modelling is utilized to simulate the recording and swelling characteristics of developed doubly photopolymerized (DP) holographic sensors. The holographic devices simplify fabrication processes, reduce financial costs, and improve biocompatibility. A holographic grating is achieved through in situ photopolymerization of a highly crosslinked polymer to produce nanostructured refractive index modulation. The unique swelling characteristics DP holographic sensors possess necessitate the development of system‐specific computational modelling. Hydrogel parameters, including film thickness, refractive index change, layer number, and external medium refractive index are examined for their effect on reflection spectra. Optimized computational models are utilized to study the effect of differential swelling rates of individual layer spacings on sensor response, indicating an idealized reduction in a swelling of 50% for the highly crosslinked region. A 2D photonic crystal geometry with additional periodicity is developed, to inform further sensor design opportunities. Optimized parameters for both 1D and 2D photonic structures will assist the further development of DP holographic sensors. [ABSTRACT FROM AUTHOR]

Anodizing of valve metals under oscillating conditions is one of versatile and reproducible methods of the preparation of one-dimensional photonic crystals. Here, an effect of anodizing voltage profile on morphology and optical properties of anodic titanium oxide photonic crystals is investigated. Samples are obtained by cyclic anodizing of titanium in ethylene glycol based electrolyte using sine, triangle, and square wave voltage versus charge density modulation. The optimization of anodizing parameters allowed us to prepare anodic titanium oxide photonic crystals with reflectance within the photonic band gap of up to 85%. Image, graphical abstract [ABSTRACT FROM AUTHOR]

In this work, the design and the performance of a two dimensional photonic structure with hexagonal geometry is numerically investigated by plane wave expansion (PWE) method. The structure consists in a zinc oxide (ZnO) substrate patterned in a hexagonal configuration with periodic holes with different radius. The photonic crystals exhibited band gaps in the near infrared wavelength range. This kind of photonic structures can be used for a wide range of optoelectronic applications. [ABSTRACT FROM AUTHOR]

Abstract Nanocomposites based on urethane-acrylate monomers stabilized at high concentration of silica nanoparticles were fabricated and investigated with the aim to produce efficient volume Bragg grating elements. Their sensitivity in the green spectral region and high modulation depth of the refractive index in the optically recorded elements are determined by the redistribution of combined monomers and silica nanoparticles, by the property of initiators of polymerization as well as by the parameters of recording process. The developed materials and methods can be used for creation of versatile photonic elements, for manipulation of optical wavefronts or beam propagation, for optical sensing. Highlights • Light sensitive nanocomposites based on urethane-acrylate monomers were developed. • Sensitivity to green lasers, high modulation of the refractive index was realized. • Correlations between the composition, recording processes and parameters of gratings were established. • 1D, 2D, 3D holographic elements were recorded. [ABSTRACT FROM AUTHOR]

Optical filter based locking system using photonic structure is explored in this research. Here, photonic structure is envisaged by the apt periodic combination of silicon and air. The proposed photonic structure interface with hardware implementation to realize the optical fiber based locking system. This paper emphasizes on both simulation outcomes which is investigated through reflectance characteristics and hardware implementation using Arduino board to display the lock/ unlock status. Finally, this work divulges that different type of locking system may be designed with varying the input parameters of photonic structures. [ABSTRACT FROM AUTHOR]

[Display omitted] • High-quality optical filters were produced by sinusoidal pulse anodisation. • Porous anodic alumina (PAA) exhibits an ordered pore structure and high reflectance. • Photonic stop-band in sinusoidal-profiled (PAA) shifts deeper into infrared region. • Polarisation dependence optical features of photonic-stop band were found in PAA. • Pulse anodising between self-ordering regimes enhances porosity contrast. Porous anodic alumina (PAA) holds promise for the realisation of high-quality optical filters with first-order photonic stop-bands (PSB λ1) located in the infrared spectral region, thereby expanding the possibility of its application in photonics and light-based industries. High-temperature (30 °C) sinusoidal pulse anodisation (SPA) of aluminium was applied to fabricate PAA with PSB λ1 in the range of 800–2500 nm. The systematic increase in the anodisation period (t p) and amplitude (A) caused a significant change in the optical properties of the PAAs, which were monitored by both transmittance and reflectance measurements. A switch from gradient-index to step-index optical filters was observed when A and t p were increased from the lowest (5 V and 100 s, respectively) to the highest (15 V and 300 s, respectively) values. The switch was ascribed to the transition between different self-ordering regimes. The finest filtering properties (PSB λ1 reflectance close to 100 %) were achieved when the SPA proceeded between diffusion and kinetic regimes, providing a better porosity/refractive index contrast within the periodic structure. The analysis under polarised light confirmed both the excellent filtering properties of the PAAs and the asymmetrical light reflectance produced through the robust and cost-effective SPA process. [ABSTRACT FROM AUTHOR]

A photonic crystal can be used for controlling light propagation by defining a photonic stop band that is decided by both the periodic structure and material. In this study, the photonic structure in butterfly wing was inversely replicated with germanium dioxide through a facile liquid phase deposition process. Precise replicas of both micro-tile array and dispersed micro-cubes were produced by adjusting the depositing conditions. This work provides the possibility that the abundant photonic crystals in nature can be further enriched by combining the merits of both artificial tailoring and constituents. [ABSTRACT FROM AUTHOR]

The planar orientation of Nematic Liquid crystal (NLC) molecules on the surface of (111) plane of silica photonic structure has been investigated. Nano voids of silica photonic crystal has been obtained by vertical deposition technique on indium tin oxide-coated substrate. NLC was infiltrated into the channels of voids in the photonic structures. Optical texture studies under with and without electric field were applied to investigate the NLC orientation. It is observed that NLC molecules in the nano voids of silica photonic structure exhibit an excellent planar alignment. This obtained hybrid composite structure on infiltration of NLC will be a promising candidate for electro optic applications. [ABSTRACT FROM PUBLISHER]

The intrinsic effects of the microstructures on the responsive properties of photonic crystals were experimentally investigated by coupling polyacrylamide on three kinds of biotemplates based on butterfly wings. The conclusion is supported by the simulation results of FDTD, which paves a new avenue to design the responsive PCs with a diversity of structures from nature and controllable responsive properties. • Humidity responsive PCs were fabricated by using PAAm as the water absorbing agent and natural photonic structured butterflies as templates. • Using the finite-different time-domain (FDTD) method to reveal the mechanism of the influence of structures on responsive properties. • Papilio paris butterflies could have higher sensitivity to refractive index changes than the Morpho butterflies. Nature provides abundant photonic structures which give a great inspiration on the synthesis of stimuli-responsive photonic crystals (PCs) with unique structures. However, the intrinsic effects of microstructures on the responsive properties of the hierarchical PCs are still not clear. Herein, the relationship between the photonic structures and the responsive properties is investigated by choosing three natural photonic structures replicated from templates, Morpho Menelaus and Morpho peleides both with a 1D tree-like hierarchical structure while having eight and four layers, respectively and Papilio paris , with an eight layered 1D concave structure. Humidity responsive PCs were prepared by in-situ polymerizing polyacrylamide (PAAm) onto the surface of the butterfly wing scales. The 1D concave (Papilio paris) structured PCs exhibited a higher humidity sensitivity: a wavelength redshift of 92 nm when the relative humidity rose from 11 to 97 %, as compared with the Morpho menelaus PCs, which have about 70 nm redshift for the same rise of the relative humidity. The eight layer 1D tree-like structured Morpho menelaus PCs had a higher reflectance intensity. The results were also supported by a finite-difference time-domain (FDTD) simulation. This work paves a new avenue to design responsive PCs with a diversity of structures from nature and controllable responsive properties. [ABSTRACT FROM AUTHOR]