Abstract: A method of wavefront (100) analysis including applying a transform to the wavefront, applying a plurality of different phase changes (110, 112, 114) to the transformed wavefront (108), obtaining a plurality of intensity maps (130, 132, 134) wherein the plurality of different phase changes are applied to region of the transformed wavefront, corresponding to a shape of the light source.

Abstract: A method and apparatus for wavefront analysis including obtaining a plurality of differently phase changed transformed wavefronts corresponding to a wavefront being analyzed which has an amplitude and a phase, obtaining a plurality of intensity maps of the plurality of phase changed transformed wavefronts and employing the plurality of intensity maps to obtain an output indicating the amplitude and phase of the wavefront being analyzed.

Abstract: A multi-layer optical information storage system comprising several layers of generally flat waveguide, arranged one on top of the other in a stack. The reading energy is projected through the layers perpendicularly, and is focussed onto the layer to be read. A detector disposed at the side of the layers detects the energy scattered or reflected from information or data points within the layer. The points within the layers may be in the form of defects of a type that can carry the information assigned to each point, generally by means of the presence or absence of the defect. The energy scattered or reflected from the defects in any specific layer is preferably contained within that layer because of waveguiding properties imparted to the layers by means of a graded or stepped index structure.

Abstract: The invention provides a method for producing a diffractive optical element, including forming first and second gratings, substantially in mutual registration, of at least first and second optical materials, such that for predetermined two or more wavelengths, the diffractive optical element has desired phase retardations, thereby avoiding the generation of chromatic aberrations. The invention further provides a diffractive optical element.

Abstract: A method and apparatus for wavefront analysis including obtaining a plurality of differently phase changed transformed wavefronts corresponding to a wavefront being analyzed which has an amplitude and a phase, obtaining a plurality of intensity maps of the plurality of phase changed transformed wavefronts and employing the plurality of intensity maps to obtain an output indicating the amplitude and phase of the wavefront being analyzed.