Initial-value ordinary differential equation solution via variable order Adams method (SIVA/DIVA) package is collection of subroutines for solution of nonstiff ordinary differential equations. There are versions for single-precision and double-precision arithmetic. Requires fewer evaluations of derivatives than other variable-order Adams predictor/ corrector methods. Option for direct integration of second-order equations makes integration of trajectory problems significantly more efficient. Written in FORTRAN 77.

Solving Ordinary Differential Equations

The Self-Organizing Map (SOM) algorithm has attracted a great deal of interest among researches and practitioners in a wide variety of fields. The SOM has been analyzed extensively, a number of variants have been developed and, perhaps most notably, it has been applied extensively within fields ranging from engineering sciences to medicine, biology, and economics. We have collected a comprehensive list of 5384 scientific papers that use the algorithms, have benefited from them, or contain analyses of them. The list is intended to serve as a source for literature surveys. The present addendum contains 2092 new articles, mainly from the years 1998-2002. We have provided a keyword index to help finding articles of interest, and additionally a modern automatically constructed variant of a thematic index: a WEBSOM interface to the whole article collection of years 1981-2000. The SOM of SOMs is available at http://websom.hut.fi/websom/somref/search.cgi for browsing and searching the collection.

Bibliography of Self-Organizing Map SOM) Papers: 1998-2001 Addendum

We review the history and current status of ion exchanged glass waveguide technology. The background of ion exchange in glass and key developments in the first years of research are briefly described. An overview of fabrication, characterization and modeling of waveguides is given and the most important waveguide devices and their applica- tions are discussed. Ion exchanged waveguide technology has served as an available platform for studies of general waveguide properties, in- tegrated optics structures and devices, as well as applications. It is also a commercial fabrication technology for both passive and active wave- guide components. C 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).

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Ion-exchanged glass waveguide technology: a review

Scatterometry is one of the few metrology candidates that has true in situ/in-line potential for deep submicrometer critical dimension (CD) and profile analysis. Most existing scatterometers are designed to measure multiple incident angles at a single wavelength on periodic gratings. We extend this idea by deploying specular spectroscopic scatterometry. Specular spectroscopic scatterometry (SS) is designed to measure the zeroth-order diffraction response at a fixed angle of incidence and multiple wavelengths. This mechanism allows the use of existing thin-film metrology equipment, such as spectroscopic ellipsometers, to accurately extract topographic profile information from one-dimensional (1-D) periodic structures. In this work, we developed the grating tool-kit (gtk), which implements several variants of rigorous coupled-wave analysis (RCWA) to accurately and efficiently simulate diffraction behavior of 1-D gratings. Theoretical simulations using this package show that specular spectroscopic scatterometry can be applied in the current semiconductor manufacturing technology, and can be easily extended to the 0.07-/spl mu/m generation. We have also applied a library-based profile extraction methodology to resist and poly focus-exposure matrices patterned using 0.25and 0.18-/spl mu/m lithography and etch technology, respectively, to extract their cross-sectional profiles. Discrepancies between CD-SEM, CD-AFM, and SSS measurements are discussed and explained.

Specular spectroscopic scatterometry

An approximate closed-form expression for the loss in a planar phase grating is derived by using coupled-mode theory. It is shown that this loss expression can be used to determine the spectral and angular width of a resonant-grating filter. A resonant-grating filter is a free-space optic that takes advantage of grating resonances to create narrow-band reflection peaks. Design characteristics, such as bandwidth, have previously been determined by profiling the resonance in reflectivity with the use of numerically intensive vector-diffraction methods such as rigorous coupled-wave analysis. The coupled-mode approach described here, however, gives the resonant-filter width directly, without the need to profile the resonance. Therefore computation time and hence design time are reduced. In addition, it is shown that the coupled-mode approach provides physical insights into the factors contributing to filter bandwidth.

Coupled-mode theory of resonant-grating filters

The operation of optical narrowband reflection filters based on resonance anomalies of waveguide gratings is well established for gratings of infinite extent. We investigate the properties of finite-aperture waveguide-grating resonance filters by means of rigorous electromagnetic theory and an approximate model. The rigorous approach illustrates the scattering of optical energy from the guided mode at and near the edges of the element, which leads to a reduced diffraction efficiency into the backward-diffracted zeroth order. The approximate approach provides an optical-engineering model for the estimation of the minimum grating size required to achieve a high resonance-wavelength reflectivity.

Guided-mode resonance filters of finite aperture

Optical scatterometry is a method for the on-line measurement of the geometry of a diffraction grating, which is deduced from diffraction-pattern data. We demonstrate the use of a neural network as a promising method for performing an accurate quantitative characterization of the geometry. As an example, we show the deduction of the geometry of a grating with subwavelength grooves with a rms accuracy of 1.9° for the slope of the groove walls, 0.7 nm for the linewidth, and 1.0 nm for the groove depth.

Optical scatterometry of subwavelength diffraction gratings: neural-network approach

Simulation of field-assisted ion exchange for glass channel waveguide fabrication: effect of nonhomogeneous time-dependent electric conductivity

We experimentally optimize double-ion-exchange process parameters to achieve a designed phase modulation for a wave front passing through a computer-generated waveguide hologram and numerically analyze the effects of fabrication errors. We also demonstrate a gradient-thickness waveguide hologram for⅛ beam splitting.

Double-ion-exchange process in glass for the fabrication of computer-generated waveguide holograms

Characterization of microstructures with features from submicrometers to hundreds of micrometers requires versatile methods. Profilometry and optical microscopy cannot cope with submicrometer features, and atomic-force microscopy, scanning-electron microscopy, and near-field microscopy are inherently slow, off-line methods. In optical scatterometry, the laser light scattered from a sample is measured and the sample profile is subsequently characterized. We propose the use of a two-stage model based on neural networks: rough categorization followed by refinement, thus reducing the need for prior information on the sample. We simulate the method for a submicrometer diffraction grating characterized by five parameters. It is shown that intensity measurements of few diffraction orders by use only of one wavelength are enough to yield rms errors of less than 2 nm for the parameters (approximately 2–3% of the optimal values of the parameters).

Jyrki Saarinen

Papers

Guided-mode resonance filters of finite aperture

Optical scatterometry of subwavelength diffraction gratings: neural-network approach

Simulation of field-assisted ion exchange for glass channel waveguide fabrication: effect of nonhomogeneous time-dependent electric conductivity

Double-ion-exchange process in glass for the fabrication of computer-generated waveguide holograms

Characterization of diffraction gratings in a rigorous domain with optical scatterometry: hierarchical neural-network model.