Yeda Research and Develpment & Co. Ltd

Other

The Weizmann Institute of Science

The Weizman Institute of Science

Yeda Research & Devel Co., Ltd.

Asher Albert Friesem

Yaakov Amitai

Erez Hasman

Nir Davidson

Yochay Danziger

Silviu Reinhorn

Ram Oron

Amiel A Ishaaya

Isaac Shariv

Liran Shimshi

Yaron Silberberg

Barak Dayan

Shmuel Blit

Moti Fridman

Avi Peer

Avner Zvi Sharon

Shachar Gorodeisky

Measuring polarization profile along an input optical beam cross-section using an optical system includes a polarization beam splitting assembly for splitting the input beam into a predetermined number of beam components with a predetermined polarization relation between them, and including a polarization beam splitter in an optical path of the input beam splitting it into beam components having a polarization relationship and a birefringent element in an optical path of the beam components for splitting each of them into a pair of beams having ordinary and extraordinary polarizations, thereby producing the predetermined number of output beam components. The pixel matrix is located in substantially non-intersecting optical paths of the output beam components and generates a number of output data pieces indicative of intensity distribution within the output beam components and data contained therein being indicative of the polarization profile along the input beam cross-section.

System and method for polarization measurement

A resonator cavity (A) and method are provided. The resonator cavity (A) includes at least one gain medium () and end reflectors () which define together longitudinal modes of light in the cavity, and further includes an intra-cavity beam coupler assembly (). The beam coupler assembly () is configured to split light impinging thereon into a predetermined number of spatially separated light channels, and to cause phase locking and at least partial coherent combining of the light channels, having common longitudinal and transverse modes, in a double pass through the beam coupler assembly (). The resonator cavity (A) is configured and operable to produce at least one output combined light channel of a predetermined intensity profile.

Resonator cavity configuration and method

A resonator cavity (A) and method and presented. The resonator cavity (A) comprises at least one gain medium () and end reflectors () which define together longitudinal modes of light in the cavity, and further comprises an intra-cavity beam coupler assembly (). The beam coupler assembly () is configured to split light impinging thereon into a predetermined number of spatially separated light channels, and to cause phase locking and at least partial coherent combining of the light channels, having common longitudinal and transverse modes, in a double pass through the beam coupler assembly (). The resonator cavity (A) is configured and operable to produce at least one output combined light channel of a predetermined intensity profile.

A method and device are provided for automatically generating a key and a conjugate key to be used in an optical code division multiple access system. The method comprises applying a down conversion process to pump input light to thereby produce down converted broadband signal and idler fields that are complex conjugates of each other. The signal and idler fields thus serve as the key and its conjugate. Also provided according to the invention is a method for use in coding/decoding a signal in an optical code division multiple access system.

Method and system for use in optical code division multiple access

An optical resonator supporting two sets of simultaneously co-existent oscillation modes (and), having polarizations orthogonal to each other. Mode control elements (and), such as apertures and phase elements, are introduced into the resonator to allow only preferred modes to exist. The placement and orientation of the sets are designed such that the high intensity zones of one set fall on the nodes or low intensity zones of the other set in an interlaced pattern. Thus, in a laser resonator, better utilization of the gain medium () is achieved and the beam quality and brightness over multimode lasing are improved. This configuration improves the performance of high Fresnel number resonators, in both pulsed and continuous lasers, for applications such as scribing, drilling, cutting, target designation and rangefinding. An application of the intra-cavity coherent summation of orthogonally polarized modes is described, whereby azimuthally or radially polarized beams may be obtained.

Optical resonators with orthogonally polarized modes

A discontinuous phase element ( ) is disposed between the reflector ( ) elements of an optical resonator in order to suppress unwanted modes propagating within the cavity, and to preferentially allow the existence of preferred modes within the cavity. The discontinuous phase element ( ) operates by producing sharp changes in the phase distribution of the undesirable modes, so that their propagation losses are sufficiently high prevent their build-up. This is achieved by introducing a discontinuous phase change to these modes at locations where they have high intensity. At the same time, the desired modes suffer 0 or 2&pgr; phase change, or have low intensity at the discontinuity, and so are unaffected by the discontinuous phase element. Such elements can be used in a single element or a double element configuration, and can be used in passive cavities or active cavities, such as lasers. In addition to being able to improve the output beam quality of a laser by encouraging output of the lowest order mode beam, they can also be used to improve the maximum power output of solid state lasers by encouraging the output of specific higher order mode beams, without limiting dynamic range of the laser. They can also be used to compensate for birefringence distortion in the gain medium.

Optical resonators with discontinuous phase elements

The invention provides a holographic optical device, including a light-transmissive substrate; a first holographic optical element carried by the substrate; at least one second holographic optical element carried by the substrate laterally of the first holographic optical element, and at least one third holographic optical element carried by the substrate laterally displaced from the first and second holographic optical elements; wherein the center of at least one of the first, second or third holographic optical elements is located outside a single, straight line.

Holographic optical devices

A multilevel diffractive optical element comprising a base and a plurality of phase zones having phase levels of a substantially identical height h, each phase zone being defined by a local modulation depth d and a local number of phase levels &xgr;&equals;d/h, the local number of phase levels &xgr; per phase zone being a real number, an integer of which defines the number of complete levels in the phase zone, which complete levels have identical widths, and a fraction of which, in at least one phase zone, defines an incomplete level which is narrower than the complete levels, said local number of phase levels &xgr;&equals;&xgr;(x, y) varying among different phase zones so as to provide corresponding variation of said local modulation depth d&equals;d(x, y) whereby local diffraction efficiencies and consequently an overall diffraction efficiency of the optical element is arbitrarily controlled.

Multilevel diffractive optical element

This invention discloses an electro-optically controlled optical element including a diffraction grating, and a planar waveguide associated with the diffraction grating, the diffraction grating and planar waveguide being configured to undergo resonance of at least one of transmitted or reflected light at a wavelength which is selectable by means of an electrical input.

Active wavelength selection with resonant devices

A planar optical correlator including at least first and second optical substrates (,), through which light propagates by means of total internal reflection, at least first and second holographic lenses (,) on the first optical substrate and optical third and fourth holographic lenses (,) on the second optical substrate, each of the first and second and third and fourth holographic lenses performing a Fourier transformation on the input light to their respective optical substrates, the substrates positioned such that the second and third holographic lenses at least partially face each other. A filter (,) is positioned between the second and third holographic lenses.

Compact planar optical correlator

A planar optical crossbar switch comprising two thin planar substrates, on each of which are recorded or attached two holographic lenses between which light propagates by means of total internal reflection. The first lens is a negative cylindrical lens, used to input the incident light signal to the substrate, and the second lens is a positive cylindrical lens. The two substrates are disposed at right angles to each other in such a way that the positive lenses are positioned one on top of the other with a spatial light modulator sandwiched between them or beneath them. A linear array of detectors collects the output signal from the negative lens on the second substrate. Light from an element in the linear array of sources is spread out, by means of the negative cylindrical holographic lens on the first substrate, across a row of the SLM, and light from a column of the SLM is focused by means of the cylindrical holographic lenses on the second substrate, onto a particular element of the linear array of output detectors. To connect a signal form the ith source in the input array to the jth detector in the output array, the value of the &lcub;i,j&rcub; pixel of the SLM matrix should be in the ON state.

Compact optical crossbar switch

A holographic optical device includes a light transmissive substrate carrying first and second laternally separated holographic optical elements. The first holographic optical element diffracts incident light into the substrate where it is trapped by internal reflection so that light impinges more than once at different angles at different locations on at least one of the first and second holographic optical elements with a significantly higher efficiency for one angle of incidence. The second holographic optical element diffracts light out of the substrate. The second holographic optical element may be a display hologram for displaying a three-dimensional image.

Planar holographic optical device for beam expansion and display

A holographic optical device having a light transmissive substrate with a first holographic optical element carried by the substrate, and a second holographic optical element also carried by the substrate but laterally offset from the first holographic optical element. The first holographic optical element diffracts waves from each data point in a display source into a collimated plane wave such that the plane wave is trapped inside the substrate by internal reflection, and the first holographic optical element also corrects field aberrations over the entire field of view by being recorded using at least one aspheric wavefront. The second holographic optical element diffracts the trapped plane waves out of the substrate.

Planar holographic optical device

A triangulation optical system and method for determining at least one coordinate of a surface of an object, along at least one coordinate axis which is substantially transverse to the surface. The method includes the steps of providing incident light of a substantially wide wavelength bandwidth propagating along the axis. Passing the light through an axially dispersing optics so that the light of different wavelengths is focussed at different locations relative to the axis. The different locations defining a multi-colored measuring area and a distance between extreme locations along the axis defining a depth of measuring range. Further, off-axis imaging of the measuring area, detecting intensity of the image and determining the coordinate of the intersection of the surface with the measuring area.

Growing community of inventors

Rehovot, Israel

Asher Albert Friesem