Abstract: A phase volume hologram and a method for producing the phase volume hologram are described herein. The phase volume hologram is made by filling the microcavities of a porous transparent siliceous body with a polymerisable composition (e.g., liquid monomer or monomer/oligomer mixture). The filled siliceous body then has a hologram interference pattern recorded therein using a laser light that in conformity with the hologram interference pattern converts the polymerisable composition into a polymerized material (solid-phase polymer) and a non-polymerized material. In particular, the polymerized material has a volume fraction in the microcavities that is close to 1 in the vicinity of a maxima of the recorded interference pattern and close to 0 in the vicinity of a minima of the recorded interference pattern. Thereafter, the non-polymerized material is removed from the siliceous body which now resembles the phase volume hologram.

Abstract: A holographic device, which has first and second roughly coplanar and superposed holograms, which are illuminated by the same non-polarized light beam with at least first and second spectral compositions, the holograms each being recorded in a manner such that in its middle, the axis of the diffracted beam is perpendicular to the direction of the incident beam in this medium, the diffracted beams forming first and second angularly separated light beam with the same polarization, and having different spectral compositions.

Abstract: A phase volume hologram and a method for producing the phase volume hologram are described herein. The phase volume hologram is made by filling the microcavities of a porous transparent siliceous body with a polymerisable composition (e.g., liquid monomer or monomer/oligomer mixture). The filled siliceous body then has a hologram interference pattern recorded therein using a laser light that in conformity with the hologram interference pattern converts the polymerisable composition into a polymerized material (solid-phase polymer) and a non-polymerized material. In particular, the polymerized material has a volume fraction in the microcavities that is close to 1 in the vicinity of a maxima of the recorded interference pattern and close to 0 in the vicinity of a minima of the recorded interference pattern. Thereafter, the non-polymerized material is removed from the siliceous body which now resembles the phase volume hologram.

Abstract: The present invention discloses an optical cross-connection device. The device is fabricated by disposing liquid crystal polarization modulators on a polarization beam splitting cube. The modulators effect switching by changing the polarization state of the light signal passing through the liquid crystal cell. The beam splitting cube directs the signal according to the polarization state. Several prisms are also disposed on the cube. The prisms are used to direct the light signals inside the switch. The device is simple to make, relatively inexpensive, and compact. Because it uses standard LCD technology there are very few mechanical parts subject to fatigue and other reliability issues.

Abstract: Device for elimination of the zero order beam emerging from holograms illuminated in polarized light includes a birefringent plate (5) illuminated by both said zero order beam (3) and by a diffracted beam (4) emerging from the hologram (2). The plate is arranged and sized such that one of the beams (3, 4) emerges from the plate with its plane of polarization not appreciably rotated and such that the other of said beams emerges with its plane of polarization rotated by 90°. The device further includes a polarizer (9) illuminated by the beams (3′, 4′) emergent from the birefringent plate (5), the polarizer having its plane of maximum transmittance parallel to the plane of polarization of the diffracted beam emerging from the birefringent plate as beam (4′). The device finds industrial applicability in the optical systems of video image projectors employing active matrix liquid crystal cells.