Image multiplexing by speckle in a BSO crystal

Improvement of the dynamic range of a fiber specklegram sensor based on volume speckle recording in photorefractive materials

“…In principle, this statistical behavior must be taken into account. In several works [18][19][20][21][22][23][24][25] it has been shown that Kogelnik's theory [31] can adequately predict the experimental behavior of the diffraction efficiency for specklegrams in photorefractive materials if, as a first approximation, an average light modulation is considered, and if the interaction length, i.e. the crystal thickness, is replaced by the average of the speckle length when the latter is shorter than the crystal depth.…”

“…The imaged speckle pattern and a reference beam were mixed in a 10 mm  10 mm  10 mm BSO crystal. The average size of the speckle grains was controlled varying a pupil aperture adjacent to the lens of the speckle imaging system [17][18][19][20][21][22][23][24][25]. For a particular pupil aperture, several fringe patterns were obtained for different micro displacements of the fiber output end.…”

Influence of the volume speckle on fiber specklegram sensors based on four-wave mixing in photorefractive materials

“…In this way, the recording of a speckle pattern in a volume media such as photorefractive crystals results to be useful to extract as much information as possible from the tridimensional characteristics of the speckles. In previous papers, the diffraction properties of volume gratings of spatially modulated speckle produced by a diffuser element and recorded in photorefractive crystals of the sillenite family have been analyzed [14][15][16][17][18][19]. In this work, we take advantage of the high photosensitivity and carrier mobility of the sillenite crystal family [20,21] to achieve a real time double exposure holographic FSS by using a four-wave mixing (FWM) arrangement in a BSO (Bi 12 SiO 20 ) crystal.…”

Multi-user multiplexed scheme for decoding modulated-encoded sequential information

“…In this way, the signal spectrum can occupy an adequate dimension that allows processing it more easily. The introduction of a spatial frequency carrier through the modulation technique has been applied to optical information processing and metrology [17][18][19][20]. Our proposal consists in modulating each encrypted data with a different grating.…”