Bragg reflectors

Bradyrhizobium Bragg effects Bragg equation Braggite Bragg mirrors Bragg reflector Bragg s law Braids Brain... 

Eig. 3. Depiction of the light extraction, ie, escape cones of light emission, for various LED chip stmctures consisting of absorbing substrate devices having (a) thin window layers (top cone) (b) thick window layers (top cone and four one-half side cones) (c) thin window plus the implementation of a distributed Bragg reflector between the active layer and the substrate (top and bottom cone). Also shown is (d), the optimal stmcture for light extraction, a... 

Veldhuis G.J., Berends J.H., Heideman R.G., Lambeck P.V., An integrated optical Bragg-reflector used as a chemo-optical sensor, Pure Appl. Opt. 1998 7 (1) L23-L26. 

Convertino, A. Capobianchi, A. Valentini, A. Cirillo, E. N. M., A new approach to organic solvent detection High reflectivity bragg reflectors based on a gold nanoparticle/tcllon like composite material, Adv. Mater. 2003, 15, 1103 1105... 

We consider a radially symmetric structure as illustrated in Fig. 12.2. The guiding defect, consisting of a material of refractive index ndefect, is surrounded by distributed Bragg reflectors on both sides, where the reflectors layers are of refractive indices ni and n2. All the electromagnetic field components can be expressed in terms of the z-component of the electric and magnetic fields14. These components satisfy the scalar Helmholtz equation, which in cylindrical coordinates is given by ... 

Circular Bragg nanolasers (CBNLs) of several geometries and Bragg reflector orders were fabricated within a thin membrane of InGaAsP semiconductor material21. A cross-section of the semiconductor epitaxial structure used is illustrated... 

We have studied, theoretically and experimentally, the characteristics of a novel class of lasers that are based on radial Bragg reflectors. Lasing action with low threshold levels are demonstrated at room temperature under pulsed optical pumping. The observed Q factors are in the order of several thousands. The unique characteristics on these lasers make them promising candidates for numerous applications in telecommunications, sensing, and basic research. 

In conclusion, it has been demonstrated that the manufacture of waveguides, Bragg reflectors, Fabry-Perot filters and anti-reflective coatings can be based on PS thin films. Such filters are applied for example in gas sensors, as described in the preceding section. 

Other types of optical microcavities employing the DBR mechanism of light confinement include planar annular Bragg resonators (Scheuer, 2005), based on a radial defect surrounded by Bragg reflectors, and their 3-D equivalent, spherical Bragg onion resonators (Liang, 2004). 

To demonstrate the method an example of a slow-wave optical structure is modelled. Such structures consist of a cascade of directly coupled optical resonators in order to enhance the nonlinear effects. The structure used here was recently defined within Working Group 2 of the European Action COST Pll (http //w3.uniromal.it/energetica/slow waves.doc). One period of the structure consists of one-dimensional Fabry-Perot cavity placed between two distributed Bragg reflectors (DBR) and can be described by the sequence... 

Bragg reflector - [LIGHTGENERATION - LIGHT-EMITTING DIODES] (Vol 15)... 

Bragg Reflector Mirrors and ZnO Quantum Well Structures... 

First successful ZnO device demonstrations as for example stable homo-and heteroepitaxial pn-junctions and LED structures, thin film scintillators, and quantum well structures with optical confinement, and oxide-based Bragg reflectors, and high-quality Schottky contacts are based on PLD grown thin films. Several techniques as for example the PLD in UHV conditions (laser MBE), and gradient and combinatorial PLD, and high-pressure PLD for nano-heterostructures show the innovative potential of the advanced growth technique PLD. 

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