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We present a computer-aided design tool for ion optical devices using the adjoint variable method. Numerical methods have been essential for the development of ion optical devices such as electron microscopes and mass spectrometers. Yet, the detailed computational analysis and optimization of ion optical devices is still onerous, since the governing equations of charged particle optics cannot be solved in closed form. Here, we show how to employ the adjoint variable method on the finite-element method and Störmer-Verlet method for electrostatic charged particle devices. This method allows for a full sensitivity analysis of ion optical devices, providing a quantitative measure of the effects of design parameters to device performance, at near constant computational cost with respect to the number of parameters. To demonstrate this, we perform such a sensitivity analysis for different freeform N-element Einzel lens systems including designs with over 13,000 parameters. We further show the optimization of the spot size of such lenses using a gradient-based method in combination with the adjoint variable method. The computational efficiency of the method facilitates the optimization of shapes and applied voltages of all surfaces of the device.

We performed a parametric study to suppress secondary phases in lithium niobate thin films by using pulsed laser deposition (PLD). By reducing the growth rate and changing the ambient gas pressure respectively, we found that the main parameter suppressing secondary phases is controlling the plume strength. For investigating the relation between film phases and the plume strength, extensive parametric studies were performed by changing the oxygen ambient pressure, the target to substrate distance, and also the Li content in the target. The surface morphologies of single phase films obtained with different deposition parameters are compared and deposition parameters to achieve lower loss single-phase films are discussed.

We present two different techniques on how to realize a content-addressed holographic memory when using phase-code multiplexing, relying on simple intensity measurements rather than phase distributions. Theoretical and experimental results of associative recall in a phase-coded system designed for digital data storage will be presented and compared to the corresponding method when using angular multiplexing.

We consider holographic optical data storage systems implemented with photorefractive media. Our viewpoint emphasizes the close interaction between materials and device issues. First we discuss our current understanding of photorefractive physics as it pertains to the holographic data storage problem. Then we consider architecture issues, including angular, phase-encoded, and wavelength-multiplexing techniques, and several approaches to increasing the signal-to-noise ratio of the recordings. Finally, we discuss materials issues related to crystal growth and how crystal quality impacts the performance of data storage systems. Both bulk and fibre crystal growth techniques are reviewed.

The visualization of flows in two dimensions by using planar laser light sheets is a commonly used technique. We extend this technique to three dimensions by rapidly scanning the laser light sheet to obtain a set of “slices” of the flow around a full span delta wing. The leading edge vortices, which are marked with smoke, are unburst by tangential blowing around the leading edges at angles of attack in excess of 25°. Since the measurement period is on the order of the smallest convective time scale, we obtain a virtually instantaneous set of planar cross sections of the flow. Software based on the marching cubes algorithm is used to stack the slices and reconstruct a three-dimensional surface of the smoke-seeded fluid. This surface, which corresponds to the vortices, clearly shows the qualitative effects of blowing on the delta wing flow.

We performed a parametric study to suppress secondary phases in lithium niobate thin films by using pulsed laser deposition (PLD). A KrF excimer laser (λ=248nm) was used as a PLD source and c-oriented sapphire was used as substrates, for waveguide applications. By reducing the growth rate and changing the ambient gas pressure respectively, we found that the main parameter suppressing a secondary phase is controlling the plume strength. To investigate the relation between film phases and the plume strength, extensive parametric studies were performed by changing the oxygen ambient pressure, the target to substrate distance, and also the Li content in the target. The surface morphologies of single phase films and Li-deficient phase mixed films are compared and related to the growth mechanism with a lattice misfit. Deposition parameters to achieve lower loss films are also discussed.

A three-dimensional auto-correlation function is proposed as a tool to analyse 3-D fluid flow datasets. In order to test this concept, we analysed time and space evolving datasets obtained from visualizations of the flow over a half-span delta wing. The processed slices show that the regions with strong vortical motion can easily be detected. However, it is much more difficult to determine the cross-stream velocity components. Obviously, some aspects need more attention before we can decide on the usefulness of this technique: (1) the effect of resolution and noise; (2) the smoothness of the smoke field must be controlled in order to get a large grey scale value variance; (3) the time interval between two recordings must correspond to the time scale of the cross stream motions; (4) the test flow must be less complex.

Epitaxial SBN:61 films have been grown on SBN:75 and MgO substrates by pulsed laser deposition. The optical loss due to absorption is greatly reduced by increasing the oxygen pressure to 1 mbar during the cooling process. In homoepitaxy, X-ray phi scans on the (221) plane of the SBN:61 films indicate that the in-plane grains are rotated 0° or ±28° with respect to single crystalline SBN:75 substrates. Cross-section and plane view high resolution TEM reveals this crystalline relations and microstructure of SBN thin films. Pr doped SBN:61 thin films show sharp transition band at 495 nm and 607 nm in room temperature photoluminescence measurement.

We report the epitaxial growth of Sr0.6iBa0.39Nb2O6 (SBN) thin films on MgO substrates by pulsed laser deposition. Rutherford backscattering analysis shows that the films have stoichiometric composition, identical to the target, and thicknesses in the range 200–400 nm. X-ray diffraction 2θ-scans indicate layers with the (001) orientation perpendicular to the substrate plane, and phi scans on the (221) plane reveal that the films have two pairs of in-plane orientations. The orientations correspond to a rotation of the SBN unit cell relative to the MgO unit cell of ± 18.6° and ± 30.9° respectively. Waveguide characterization shows waveguides supporting up to four modes and film refractive indices which compare well with those of bulk SBN.