Showing papers by "Leslie Greengard published in 2006"
TL;DR: A wideband version of the Fast Multipole Method for the Helmholtz equation in three dimensions is described, which is accurate and efficient for any frequency, having a CPU time of O(N) if low-frequency computations dominate, or O( NlogN)if high-frequency Computations dominate.
297 citations
TL;DR: The technique makes use of the plasmon resonance in nanoscale metal structures to produce the local heating necessary to initiate deposition when illuminated by a focused low-power laser, and can be used to spatially control the deposition of virtually any material for which a CVD process exists.
Abstract: We introduce a new chemical vapor deposition (CVD) process that can be used to selectively deposit materials of many different types. The technique makes use of the plasmon resonance in nanoscale metal structures to produce the local heating necessary to initiate deposition when illuminated by a focused low-power laser. We demonstrate the technique, which we refer to as plasmon-assisted CVD (PACVD), by patterning the spatial deposition of PbO and TiO_2 on glass substrates coated with a dispersion of 23 nm gold particles. The morphology of both oxide deposits is consistent with local laser-induced heating of the gold particles by more than 150 °C. We show that temperature changes of this magnitude are consistent with our analysis of the heat-loss mechanisms. The technique is general and can be used to spatially control the deposition of virtually any material for which a CVD process exists.
169 citations
TL;DR: In this paper, a robust integral equation method for the calculation of the electrostatic and thermal properties of systems made of piecewise homogeneous, high contrast materials is presented, which is related to the perturbation approach proposed by Tausch and White.
36 citations
31 Dec 2006
TL;DR: The fast sinc transform is described, an algorithm which computes the convolution of arbitrarily spaced data with the sinc kernel in O.N logN/ operations.
Abstract: A number of problems in image reconstruction and image processing can be addressed, in principle, using the sinc kernel. Since the sinc kernel decays slowly, however, it is generally avoided in favor of some more local but less precise choice. In this paper, we describe the fast sinc transform, an algorithm which computes the convolution of arbitrarily spaced data with the sinc kernel in O.N logN/ operations, where N denotes the number of data points. We briefly discuss its application to the construction of optimal density compensation weights for Fourier reconstruction and to the iterative approximation of the pseudoinverse of the signal equation in MRI.
30 citations