1,721,043 research outputs found
Photonic crystal X-shaped waves
No full textWe study out-of-plane three-dimensional wave localization in two-dimensional photonic crystals (PCs) and predict the existence of two types of stationary X-shaped waves at frequencies corresponding to either a local top point of a band, where the effective in-plane diffraction turns out to be negative, or at band saddle points. In the former case the X wave is directed along the invariance direction of the PC, whereas in the latter case it lies in the PC plane and directed along one of the principal directions of the diffraction tensor. Numerical results of localized waves for a PC with a square lattice, obtained in the spectral domain by superposition of isofrequency Bloch modes, are presented and confirm the analytical predictions based on an effective mass approach
Integrated devices in ferroelectrics for optical modulations and sensing
No full textWe will review the current status of domain inverted lithium niobate acousto- and electro-optic devices and show how the introduction of domain micro-engineering techniques can have a strong impact on modulators' performance enabling for a new class of integrated devices. We will also present potential applications of the proposed devices in increasingly important areas, such as advanced optical communication modulation formats, reconfigurable networks and sensors
Room temperature direct bonding of LiNbO3 crystal layers and its application to high-voltage optical sensing
No full textLiNbO3 is a crystal widely used in photonics and acoustics, for example in electro-optic modulation, nonlinear optical frequency conversion, electric field sensing and surface acoustic wave filtering. It often needs to be combined with other materials and used in thin layers to achieve the adequate device performance. In this paper, we investigate direct bonding of LiNbO 3 crystals with other dielectric materials, such as Si and fused silica (SiO2), and we show that specific surface chemical cleaning, together with Ar or O2 plasma activation, can be used to increase the surface free energy and achieve effective bonding at room temperature. The resulting hybrid material bonding is very strong, making the dicing and grinding of LiNbO3 layers as thin as 15 νm possible. To demonstrate the application potentials of the proposed bonding technique, we have fabricated and characterized a high-voltage field sensor with high sensitivity in a domain inverted and bonded LiNbO3 waveguide substrate
Arbitrary-order all-fiber temporal differentiator based on a fiber Bragg grating: design and experimental demonstration
No full textPatent number ES201131704: SISTEMA DE VISUALIZACION FRONTAL CON SUPRESION DE IMAGEN FANTASMA
No full text
- …
