scholarly journals High-energy angle resolved reflection spectroscopy on three-dimensional photonic crystals of self-organized polymeric nanospheres

2008 ◽  
Vol 16 (2) ◽  
pp. 897 ◽  
Author(s):  
S. Schutzmann ◽  
I. Venditti ◽  
P. Prosposito ◽  
M. Casalboni ◽  
M. V. Russo
2002 ◽  
Vol 722 ◽  
Author(s):  
Helmut Foell ◽  
Sergiu Langa ◽  
Juergen Carstensen ◽  
Marc Christophersen ◽  
Ivan Tiginyanu ◽  
...  

AbstractOrdered arrays of pores in Si provided the first (two dimensional) photonic crystals with bandgaps in the μm region. The paper explores the potential of pore etching for two- and threedimensional photonic crystals in GaAs, InP, and GaP. A striking feature of pore etching in III-V semiconductors is the strong tendency to self-organization and pattern formation. As an example, self-organized well-defined pore lattices (a = 100 nm – 1 μm) can be made in InP. All materials show self organized diameter oscillations, often synchronized over large distances between pores. Extremely strong diameter oscillations are observed in GaAs. Pores in all materials tend to grow in <111> directions, but can be induced to grow in the direction of current flow, too. These features can be used to produce two- and three dimensional photonic crystals. The latter goal might be achieved by switching periodically between different pore morphologies with depth, or by modulating the diameter with depth - always helped by the tendency to self organization. Self organization, however, will not lead to perfect crystal structures; lithographically defined nucleation is needed and has been tried. First results show that there are pronounced differences to what is known from Si. While the production of externally defined photonic crystals in the sub μm region appears to be feasible, the strong tendency to self organization must be taken into account by matching internal time and length scales to the desired external ones.


2007 ◽  
Vol 15 (26) ◽  
pp. 17754 ◽  
Author(s):  
Luis A. Dorado ◽  
Ricardo A. Depine ◽  
Gabriel Lozano ◽  
Hernán Míguez

2005 ◽  
Vol 71 (19) ◽  
Author(s):  
F. García-Santamaría ◽  
J. F. Galisteo-López ◽  
P. V. Braun ◽  
C. López

Author(s):  
Ted Janssen ◽  
Gervais Chapuis ◽  
Marc de Boissieu

The law of rational indices to describe crystal faces was one of the most fundamental law of crystallography and is strongly linked to the three-dimensional periodicity of solids. This chapter describes how this fundamental law has to be revised and generalized in order to include the structures of aperiodic crystals. The generalization consists in using for each face a number of integers, with the number corresponding to the rank of the structure, that is, the number of integer indices necessary to characterize each of the diffracted intensities generated by the aperiodic system. A series of examples including incommensurate multiferroics, icosahedral crystals, and decagonal quaiscrystals illustrates this topic. Aperiodicity is also encountered in surfaces where the same generalization can be applied. The chapter discusses aperiodic crystal morphology, including icosahedral quasicrystal morphology, decagonal quasicrystal morphology, and aperiodic crystal surfaces; magnetic quasiperiodic systems; aperiodic photonic crystals; mesoscopic quasicrystals, and the mineral calaverite.


2000 ◽  
Vol 15 (15) ◽  
pp. 2269-2288
Author(s):  
SANATAN DIGAL ◽  
RAJARSHI RAY ◽  
SUPRATIM SENGUPTA ◽  
AJIT M. SRIVASTAVA

We demonstrate the possibility of forming a single, large domain of disoriented chiral condensate (DCC) in a heavy-ion collision. In our scenario, rapid initial heating of the parton system provides a driving force for the chiral field, moving it away from the true vacuum and forcing it to go to the opposite point on the vacuum manifold. This converts the entire hot region into a single DCC domain. Subsequent rolling down of the chiral field to its true vacuum will then lead to emission of a large number of (approximately) coherent pions. The requirement of suppression of thermal fluctuations to maintain the (approximate) coherence of such a large DCC domain, favors three-dimensional expansion of the plasma over the longitudinal expansion even at very early stages of evolution. This also constrains the maximum temperature of the system to lie within a window. We roughly estimate this window to be about 200–400 MeV. These results lead us to predict that extremely high energy collisions of very small nuclei (possibly hadrons) are better suited for observing signatures of a large DCC. Another possibility is to focus on peripheral collisions of heavy nuclei.


2020 ◽  
Vol 15 (S359) ◽  
pp. 178-179
Author(s):  
Saqib Hussain ◽  
Rafael Alves Batista ◽  
Elisabete Maria de Gouveia Dal Pino ◽  
Klaus Dolag

AbstractWe present results of the propagation of high-energy cosmic rays (CRs) and their secondaries in the intracluster medium (ICM). To this end, we employ three-dimensional cosmological magnetohydrodynamical simulations of the turbulent intergalactic medium to explore the propagation of CRs with energies between 1014 and 1019 eV. We study the interaction of test particles with this environment considering all relevant electromagnetic, photohadronic, photonuclear, and hadronuclear processes. Finally, we discuss the consequences of the confinement of high-energy CRs in clusters for the production of gamma rays and neutrinos.


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