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Photonic crystals

Hui Wang, Bin Fang, Lin Kong, Xiangzi Li, Zhijun Feng, Yunjun Wu, Kajsa Uvdal, Zhangjun Hu
A novel donor-π-acceptor-π-donor type (D-π-A-π-D') Schiff base derivative (L) has been designed and synthesized. The structure of L is confirmed by single-crystal X-ray diffraction analysis as well. The photophysical properties of compound L were comprehensively investigated by using both experimental and theoretical methods. The results indicate that L exhibits large Stokes shift and moderate two-photon action (2PA) cross-section in the near infrared (NIR) region. Furthermore, the confocal microscopy imaging study demonstrates that compound L could penetrate into cells and target the cellular mitochondria compartment...
March 13, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Vyacheslav A Trofimov, Tatiana M Lysak, Evgenii M Trykin
We discuss a novel type of surface soliton-aberrated surface soliton-appearance in a nonlinear one dimensional photonic crystal and a possibility of this surface soliton formation in two dimensional photonic crystal. An aberrated surface soliton possesses a nonlinear distribution of the wavefront. We show that, in one dimensional photonic crystal, the surface soliton is formed at the photonic crystal boundary with the ambient medium. Essentially, that it occupies several layers at the photonic crystal boundary and penetrates into the ambient medium at a distance also equal to several layers, so that one can infer about light energy localization at the lateral surface of the photonic crystal...
2018: PloS One
Flavio Esposito, Rajeev Ranjan, Stefania Campopiano, Agostino Iadicicco
In this work, we report about our recent results concerning the fabrication of Long Period Grating (LPG) sensors in several optical fibers, through the Electric Arc Discharge (EAD) technique. In particular, the following silica fibers with both different dopants and geometrical structures are considered: standard Ge-doped, photosensitive B/Ge codoped, P-doped, pure-silica core with F-doped cladding, Panda type Polarization-maintaining, and Hollow core Photonic crystal fiber. An adaptive platform was developed and the appropriate "recipe" was identified for each fiber, in terms of both arc discharge parameters and setup arrangement, for manufacturing LPGs with strong and narrow attenuation bands, low insertion losses, and short length...
March 20, 2018: Sensors
Qiu Hong Cui, Qian Peng, Yi Luo, Yuqian Jiang, Yongli Yan, Cong Wei, Zhigang Shuai, Cheng Sun, Jiannian Yao, Yong Sheng Zhao
The ability to steer the flow of light toward desired propagation directions is critically important for the realization of key functionalities in optical communication and information processing. Although various schemes have been proposed for this purpose, the lack of capability to incorporate an external electric field to effectively tune the light propagation has severely limited the on-chip integration of photonics and electronics. Because of the noninteractive nature of photons, it is only possible to electrically control the flow of light by modifying the refractive index of materials through the electro-optic effect...
March 2018: Science Advances
L Li, A J Fijneman, J A Kaandorp, J Aizenberg, W L Noorduin
Controlling nucleation and growth is crucial in biological and artificial mineralization and self-assembly processes. The nucleation barrier is determined by the chemistry of the interfaces at which crystallization occurs and local supersaturation. Although chemically tailored substrates and lattice mismatches are routinely used to modify energy landscape at the substrate/nucleus interface and thereby steer heterogeneous nucleation, strategies to combine this with control over local supersaturations have remained virtually unexplored...
March 19, 2018: Proceedings of the National Academy of Sciences of the United States of America
Peifeng Jing, Yannan Liu, Ethan G Keeler, Nelly M Cruz, Benjamin S Freedman, Lih Y Lin
Cell manipulation is one of the most impactful applications for optical tweezers, and derived from this promise, we demonstrate a new optical tweezers system for the study of cell adhesion and organization. This method utilizes photonic-crystal-enhanced optical tweezers to manipulate cells with low laser intensities. By doing so, it enables effective cell patterning and culturing within the conditions necessary for successful differentiation and colony formation of human pluripotent stem cells. To this end, the biocompatibility of plasma-treated parylene-C for cell culturing was studied, and a thorough characterization of cellular interactive forces was performed using this system...
February 1, 2018: Biomedical Optics Express
Riccardo Rizzo, Maria Alvaro, Norbert Danz, Lucia Napione, Emiliano Descrovi, Stefan Schmieder, Alberto Sinibaldi, Subinoy Rana, Rona Chandrawati, Peter Munzert, Thomas Schubert, Emmanuel Maillart, Aleksei Anopchenko, Paola Rivolo, Alessandro Mascioletti, Erik Förster, Frank Sonntag, Molly M Stevens, Federico Bussolino, Francesco Michelotti
Quantitative detection of angiogenic biomarkers provides a powerful tool to diagnose cancers in early stages and to follow its progression during therapy. Conventional tests require trained personnel, dedicated laboratory equipment and are generally time-consuming. Herein, we propose our developed biosensing platform as a useful tool for a rapid determination of Angiopoietin-2 biomarker directly from patient plasma within 30 minutes, without any sample preparation or dilution. Bloch surface waves supported by one dimensional photonic crystal are exploited to enhance and redirect the fluorescence arising from a sandwich immunoassay that involves Angiopoietin-2...
February 1, 2018: Biomedical Optics Express
Simone Biasco, Katia Garrasi, Fabrizio Castellano, Lianhe Li, Harvey E Beere, David A Ritchie, Edmund H Linfield, A Giles Davies, Miriam S Vitiello
Terahertz (THz) quantum cascade lasers (QCLs) have undergone rapid development since their demonstration, showing high power, broad-tunability, quantum-limited linewidth, and ultra-broadband gain. Typically, to address applications needs, continuous-wave (CW) operation, low-divergent beam profiles and fine spectral control of the emitted radiation, are required. This, however, is very difficult to achieve in practice. Lithographic patterning has been extensively used to this purpose (via distributed feedback (DFB), photonic crystals or microcavities), to optimize either the beam divergence or the emission frequency, or, both of them simultaneously, in third-order DFBs, via a demanding fabrication procedure that precisely constrains the mode index to 3...
March 16, 2018: Nature Communications
Ayaka Sato, Yuya Ikeda, Koichi Yamaguchi, Varun Vohra
Facile detection and the identification of hazardous organic solvents are essential for ensuring global safety and avoiding harm to the environment caused by industrial wastes. Here, we present a simple method for the fabrication of silver-coated monodisperse polystyrene nanoparticle photonic structures that are embedded into a polydimethylsiloxane (PDMS) matrix. These hybrid materials exhibit a strong green iridescence with a reflectance peak at 550 nm that originates from the close-packed arrangement of the nanoparticles...
March 16, 2018: Nanomaterials
Cheryl Suwen Law, Siew Yee Lim, Abel Santos
This study presents a nanofabrication approach that enables the production of nanoporous anodic alumina distributed Bragg reflectors (NAA-DBRs) with finely engineered light filtering features across the spectral regions. The photonic stopband (PSB) of these NAA-based photonic crystal (PC) structures is precisely tuned by an apodization strategy applied during stepwise pulse anodization with the aim of engineering the effective medium of NAA-DBRs in depth. We systematically assess the effect of different fabrication parameters such as apodization function (i...
March 15, 2018: Scientific Reports
Alexandre Brieussel, Konstantin Ott, Maxime Joos, Nicolas Treps, Claude Fabre
In this work, we investigate three different compact fibered systems generating vacuum squeezing that involve optical cavities limited by the end surface of a fiber and by a curved mirror and containing a thin parametric crystal. These systems have the advantage to couple squeezed states directly to a fiber, allowing the user to benefit from the flexibility of fibers in the use of squeezing. Three types of fibers are investigated: standard single-mode fibers, photonic-crystal large-mode-area single-mode fibers, and short multimode fibers taped to a single-mode fiber...
March 15, 2018: Optics Letters
Anna C Tasolamprou, Thomas Koschny, Maria Kafesaki, Costas M Soukoulis
We present the design of a dielectric inverse photonic crystal structure that couples line-defect waveguide propagating modes into highly directional beams of controllable directionality. The structure utilizes a triangular lattice made of air holes drilled in an infinitely thick Si slab, and it is designed for operation in the near-infrared and optical regime. The structure operation is based on the excitation and manipulation of dark dielectric surface states, in particular on the tailoring of the dark states' coupling to outgoing radiation...
November 15, 2017: ACS Photonics
Lei Pan, Hongbo Xu, Ruizhen Lv, Jun Qiu, Jiupeng Zhao, Yao Li
The laser damage behavior of three-dimensional photonic crystals (3D-PCs) with an opal structure is investigated using both experimental and simulation methods. Polystyrene (PS) colloidal crystals films with a reflection peak at 1064 nm are used as the model material. Disordered films (DF) are fabricated with PS microspheres as contrast samples. The laser-induced damage threshold (LIDT) of 3D-PCs is tested, which is as 2.35 times high as the LIDT of DF. All laser damages are derived from defects in 3D-PCs, implying that the LIDT of ideal 3D-PCs will be significantly increased...
March 14, 2018: Scientific Reports
Jitendra B Maurya, Alexandre François, Yogendra K Prajapati
One-dimensional photonic crystal (1DPC) sensors have emerged as contenders for traditional surface plasmon resonance sensors, owing to their potential for the detection of bigger molecules and particles due to their higher interaction volume in the sensing medium. Two-dimensional layered nanomaterials, most notably graphene and dichalcogenides (e.g., MoS₂, MoSe₂, WS₂, and WSe₂), have shown higher refractive index sensitivity because of their absorption as well as adsorption property. The proposed configuration of 1DPC presented consists of alternate layers of the aforementioned nanomaterials and silicon...
March 14, 2018: Sensors
Fang Zhang, W Mx, Zhengping Wang, Kezhen Han, Xiaojuan Liu, Xinguang Xu
As the cousins of graphene, i.e. same group IVA element, the nonlinear absorption properties of silicene nanosheets were rarely studied. In this paper, we successfully exfoliated the two-dimensional silicene nanosheets from bulk silicon crystal using liquid phase exfoliation method. The nonlinear absorption properties of silicene nanosheets were systemically investigated for the first time, as we have known. Silicene performed exciting saturable absorption and two photon absorption behavior. The lower saturable intensity and larger two photon absorption coefficient at 532 nm excitation indicates that silicene has potential application in ultrafast lasers and optical limiting devices, especially in visible waveband...
March 14, 2018: Nanotechnology
Gregory Moille, Sylvain Combrié, Laurence Morgenroth, Gaëlle Lehoucq, Sébastien Sauvage, Moustafa El Kurdi, Philippe Boucaud, Alfredo de Rossi, Xavier Checoury
We demonstrate that conformal encapsulation using atomic layer deposition of GaAs nano-cavity resonator made of photonic crystal cavity prevents photo-induced oxidation. This improvement allows injecting a large quantity of energy in the resonator without any degradation of the material, thus enabling spectral stability of the resonance. We prove second harmonic and third harmonic generation over more than one decade of pump power variation, thanks to this encapsulation, with a total efficiency (ηSHG = 8.3 × 10-5 W-1 and ηTHG = 1...
March 5, 2018: Optics Express
Maurin Douix, Charles Baudot, Delphine Marris-Morini, Alexia Valéry, Daivid Fowler, Pablo Acosta-Alba, Sébastien Kerdilès, Catherine Euvrard, Romuald Blanc, Rémi Beneyton, Aurélie Souhaité, Sébastien Crémer, Nathalie Vulliet, Laurent Vivien, Frédéric Boeuf
Optical properties of poly-silicon material are investigated to be integrated in new silicon photonics devices, such as capacitive modulators. Test structure fabrication is done on 300 mm wafer using LPCVD deposition: 300 nm thick amorphous silicon layers are deposited on thermal oxide, followed by solid phase crystallization anneal. Rib waveguides are fabricated and optical propagation losses measured at 1.31 µm. Physical analysis (TEM ASTAR, AFM and SIMS) are used to assess the origin of losses. Optimal deposition and annealing conditions have been defined, resulting in 400 nm-wide rib waveguides with only 9...
March 5, 2018: Optics Express
Venkata Jayasurya Yallapragada, Hervé Rigneault, Dan Oron
Supercontinuum generation using photonic crystal fibers is a useful technique to generate light spanning a broad wavelength range, using femtosecond laser pulses. For some applications, one may desire higher power density at specific wavelengths. Increasing the pump power results primarily in further broadening of the output spectrum and is not particularly useful for this purpose. In this paper we demonstrate that by applying a periodic spectral phase modulation to the input pulse using a pulse shaper, the spectral energy density of the output supercontinuum can be enhanced by nearly an order of magnitude at specific wavelengths, which are tunable...
March 5, 2018: Optics Express
Kristian Tølbøl Sørensen, Charlotte Bonde Ingvorsen, Line Hagner Nielsen, Anders Kristensen
A photonic crystal slab (PCS) sensor is a universal refractive index sensor with possibilities and performance very similar to surface plasmon resonance (SPR), which represents the gold standard of biosensing. Cheap PCS sensors can be made vacuum-free entirely out of polymers, but come with additional challenges, besides those relating to temperature-variations, which must be considered in any refractive index based method: The polymeric waveguide core was found to swell by ∼0.3% as water absorbed into the waveguide core over ∼1...
March 5, 2018: Optics Express
Zayakhuu Gerelkhuu, Bui The Huy, Mirkomil Sharipov, Dasom Jung, The-Long Phan, Eric D Conte, Yong-Ill Lee
Upconversion nanoparticles (UCNPs) possess a unique type of photoluminescence (PL) in which lower-energy excitation is converted into higher-energy emission via multi-photon absorption processes. In this work, we have used a facile one-step hydrothermal method promoted water solubility to synthesis NaLuGdF4 :Yb3+ /Er3+ (Tm3+ ) UCNPs coated with malonic acid (MA). Scanning electron microscopy images and X-ray diffraction patterns reveal sphere-shaped UCNPs with an average size of ~80nm crystallized in the cubic NaLuF4 structure...
May 1, 2018: Materials Science & Engineering. C, Materials for Biological Applications
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