118,461 research outputs found
Method for holographic storage using peristrophic multiplexing
A method of multiplexing holograms by rotating the material or, equivalently, the recording beams is described. Peristropic (Greek for rotation) multiplexing can be combined with other multiplexing methods to increase the storage density of holographic storage systems. Peristrophic multiplexing is experimentally demonstrated with Du Pont's HRF-150 photopolymer film. We multiplexed a total of 295 holograms in a 38-μm-thick photopolymer film by combining peristrophic multiplexing with angle multiplexing
Free Space Optical Polarization De-multiplexing and Multiplexing by means of Conical Refraction
Polarization de-multiplexing and multiplexing by means of conical refraction
is proposed to increase the channel capacity for free space optical
communication applications. The proposed technique is based on the
forward-backward optical transform occurring when a light beam propagates
consecutively along the optic axes of two identical biaxial crystals with
opposite orientations of their conical refraction characteristic vectors. We
present experimental proof of usefulness of the conical refraction
de-multiplexing and multiplexing technique by increasing in one order of
magnitude the channel capacity at optical frequencies in a propagation distance
of 4m
Folded shift multiplexing
Shift multiplexing is a holographic recording method that uses a spherical reference wave. We extend the principle to a thin slab of holographic material that acts as a waveguide. Total internal reflection folds the reference spherical beam in one dimension. We demonstrate that the shift selectivity with the folded spherical beam is independent of the slab thickness but depends instead on the numerical aperture of the coupled spherical wave. A shift selectivity of 0.5 µm has been achieved with a 1-mm-thick LiNbO3 crystal and 50 high-definition data pages are recorded with this method
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