Ioseph Gurwich

Planar configuration for image projection.

A flat panel, compact virtual image projection display is presented. It is based on a light- guided optical configuration that includes three linear holographic gratings recorded on one planar transparent substrate so as to obtain a magnified virtual image for a small input display. The principles of the projection display, unique design, and procedures for experimentally recording an actual planar configuration are presented, along with evaluation results. The results reveal that a field of view of +/-8 degrees can be readily achieved at a distance of 36 cm, making such planar configurations attractive for head-up displays.

Scattering of electromagnetic radiation by multilayered spheroidal particles: recursive procedure

A formalism is developed for the calculation of the electromagnetic field scattered by a multilayered spheroidal particle. The suggested formalism utilizes the recursive approach with respect to passing from one layer to the next; thus it does not require an increase in the size of the equation matrices involved as the number of layers increases. The equations operate with matrices of the same size as for a homogeneous spheroid. The special cases of extremely prolate and weakly prolate spheroids are considered in more detail. It is shown that in such cases one can avoid the matrix calculations by instead using the iterative scalar calculations.

The recursive algorithm for electromagnetic scattering by tilted infinite circular multilayered cylinder

Abstract The purpose of the paper is to develop a formalism for solving the problem of scattering of electromagnetic waves by a tilted, infinite, multilayered cylinder. The approach allows us to obtain the Mie scattering coefficients without involving matrix calculations. This method provides the basis for constructing an efficient algorithm for the case of a multilayered cylinder, extending the procedure developed for a multilayered sphere. For the case of a cylinder, such a procedure does not follow directly from the boundary conditions, but requires a special mathematical justification. The proof is presented in this study.

Design and experiments of planar optical light guides for virtual image displays

Planar optical light guides that are suitable for compact, relatively large virtual image projection displays, of either see-through or non-see-through capabilities, are presented. Such light guides are comprised of three diffractive elements that are recorded on a single substrate. The basic principles, design methods, experimental procedures, calculated as well as experimental results are presented. The results reveal that a relatively large field of view and uniform luminance over the entire output image can be obtained, even when the distance from the light guide to the viewer is relatively large.

Scattering by an arbitrary multi-layered spheroid: theory and numerical results

In this paper a simple algorithm is presented for calculating light scattering by a multi-layered spheroid for both normal and oblique incidence. Results of several numerical tests are given. They present the extinction efficiency for different aspect-ratio spheroids in comparison with that of the proper multi-layered sphere and cylinder.

Replication of diffractive arrays on planar light guides by soft nanolithography

The development of replication processes of arrays of diffractive optical elements (DOEs) on planar substrates serving as optical light-guides (OLGs) by soft nano-lithography are described.The master DOE arrays were recorded by holographic interferometry in photoresist on the OLG substrate. These master OLGs carrying nanometer surface-relief grating structures were then transferred into a thermally curable Si-elastomer serving as the molding tool for the production of the replica. The replica were formed by casting UV-curable photopolymers onto a planar substrate inserted into the mold. The replication process variables were then designed and evaluated by the statistical Taguchi technique. The replica OLGs were compared to the master OLGs both in terms of surface flatness and grating fidelity. The results show that optimal processes yielded both good OLG flatness (

Analytical approximation for multiple Raman-Mie scattering

An analytical solution for calculation of double Raman-Mie scattering in the presence of a cloud is suggested. The model includes the Raman-Mie and Mie-Raman scattering processes occurring in the cloud volume as well as integrated Raman scattering signal from air molecules along the laser pulse from lidar to the cloud base. The developed algorithm allows for the comparison of relative contribution of these processes to the total Raman-shifted lidar signal. For typical lidar and cloud parameters, double scattering is not negligible and its contribution to the Raman signal is around 20%.

Scattering from a long helix

We consider here the electromagnetic wave scattering by a long and thin-wire helical particle. In contrast to several previous theoretical works, we adopt here the Mie theory to this case. In the present work a long helical particle is considered as a hollow cylinder with a thin non-homogeneous membrane for which the periodical boundary conditions are imposed.