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Practical Implementation of Prestack Kirchhoff Time Migration on a General Purpose Graphics Processing Unit

Liu G., Li C.

Acta Geophysica

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2016

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Vol. 64, no. 4

1051--1063

EN

In this study, we present a practical implementation of prestack Kirchhoff time migration (PSTM) on a general purpose graphic processing unit. First, we consider the three main optimizations of the PSTM GPU code, i.e., designing a configuration based on a reasonable execution, using the texture memory for velocity interpolation, and the application of an intrinsic function in device code. This approach can achieve a speedup of nearly 45 times on a NVIDIA GTX 680 GPU compared with CPU code when a larger imaging space is used, where the PSTM output is a common reflection point that is gathered as I[nx][ny][nh][nt] in matrix format. However, this method requires more memory space so the limited imaging space cannot fully exploit the GPU sources. To overcome this problem, we designed a PSTM scheme with multi-GPUs for imaging different seismic data on different GPUs using an offset value. This process can achieve the peak speedup of GPU PSTM code and it greatly increases the efficiency of the calculations, but without changing the imaging result.

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Dipole and quadrupole surface plasmon resonance contributions in formation of near-field images of a gold nanosphere

Shopa M., Kolwas K., Derkachova A., Derkachov G.

Opto-Electronics Review

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2010

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Vol. 18, No. 4

421-428

EN

Multipolar plasmon optical excitations at spherical gold nanoparticles and their manifestations in the particle images formatted in the particle surface proximity are studied. The multipolar plasmon size characteristic: plasmon resonance frequencies and plasmon damping rates were obtained within rigorous size dependent modelling. The realistic, frequency dependent dielectric function of a metal was used. The distribution of light intensity and of electric field radial component at the flat square scanning plane scattered by a gold sphere of radius 95 nm was acquired. The images resulted from the spatial distribution of the full mean Poynting vector including near-field radial components of the scattered electromagnetic field. Monochromatic images at frequencies close to and equal to the plasmon dipole and quadrupole resonance frequencies are discussed. The changes in images and radial components of the scattered electromagnetic field distribution at the scanning plane moved away from the particle surface from near-field to far-field region are discussed.

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Moving from micro- to nanoworld in optical domain scanning probe microscopy

Radojewski J.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2006

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Vol. 54, nr 1

25-32

EN

In the article we described the evolution of optical technology tram lens-type microscopes working in far-field to SNOM (Scanning Near-Field Optical Microscopy) constructions. We considered two systems elaborated in our laboratory, namely PSTM system (photon Scanning Tunelling Microscope) and SNOM system. In both systems we obtained subwavelength resolution. Same details about optical point probe technology in both systems are given and experimental results presented.