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Signal beam

About: Signal beam is a research topic. Over the lifetime, 1881 publications have been published within this topic receiving 20717 citations.


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Patent
09 Aug 2002
TL;DR: In this paper, the reference beam is a phase beam which consists essentially of a multitude of rays of varying angle of incidence and non-uniform phase, in which the process comprises changing the orientation of the phase beam for recording or reconstructing different holograms.
Abstract: Holography in which an array of overlapping holograms is recorded or reconstructed in a recording medium, holograms being produced by interference of a reference beam and a signal beam, in which the reference beam is a phase beam which consists essentially of a multitude of rays of varying angle of incidence and non-uniform phase, in which the process comprises changing the orientation of the phase beam for recording or reconstructing different holograms, wherein phase beam orientation is changed relative to the medium while maintaining the medium stationary in order to enable recording or reconstruction of individual holograms at a given location of the medium.

26 citations

Patent
20 Nov 1995
TL;DR: In this paper, a liquid level sensor includes a modulated laser diode and collimating optics for collimating the diode output to produce an optical measurement signal beam transmitted to the fluid boundary through a diffuser to diverge the beam.
Abstract: The liquid level sensor includes a modulated laser diode and collimating optics for collimating the diode output to produce an optical measurement signal beam transmitted to the fluid boundary through a diffuser to diverge the beam. A detector detects reflections of the beam from the fluid boundary to produce an output signal which is amplified and inverted to drive the modulator. The frequency of the modulation, which depends on the distance to the fluid boundary, is measured and the distance is derived from that measurement.

26 citations

Journal ArticleDOI
TL;DR: A complete understanding of the phenomenon of polarization attraction in these two systems is provided, which allows to achieve a control of the polarization state of the signal beam by adjusting the polarization of the pump.
Abstract: We consider the counterpropagating interaction of a signal and a pump beam in a spun fiber and in a randomly birefringent fiber, the latter being relevant to optical telecommunication systems. On the basis of a geometrical analysis of the Hamiltonian singularities of the system, we provide a complete understanding of the phenomenon of polarization attraction in these two systems, which allows to achieve a control of the polarization state of the signal beam by adjusting the polarization of the pump. In spun fibers, all polarization states of the signal beam are attracted toward a specific line of polarization states on the Poincare sphere, whose characteristics are determined by the polarization state of the injected backward pump. In randomly birefringent telecommunication fibers, we show that an unpolarized signal beam can be repolarized into any particular polarization state, without loss of energy.

26 citations

Patent
08 Apr 1998
TL;DR: In this paper, a spatial light modulator capable of modulating the polarization of the beam incident on each pixel is presented. But the modulator provides information of bit of two-dimensional data to each corresponding pixel by application or non-application of a voltage, and modulates the polarisation of the signal incident on the pixel.
Abstract: An optical storage medium of the present invention enables storage of data with high precision at high speed, and rewriting of data at high speed without an erasing process. Optical storage, reading and retrieving methods and optical storage, reading, and retrieving apparatuses using the medium are also provided. The optical storage medium has at least a polarization-sensitive member having the photo-induced birefringence property, such as a member made of polyester polymer having cyanoazobenzene as a side chain. The above apparatuses have spatial light modulator capable of modulating polarization. The modulator provides information of bit of two-dimensional data to each corresponding pixel by application or non-application of a voltage, and modulates the polarization of the beam incident on each pixel. Thereby, a signal beam transmitted through the spatial light modulator having a spatial polarization modulation corresponding to the two-dimensional data is obtained. The signal beam illuminates the optical storage medium, and at the same time, a reference beam illuminates the same region in the medium where the signal beam illuminates. Thus a hologram of the polarization modulation of the signal beam corresponding to the two-dimensional data is stored in the optical storage medium.

26 citations

Patent
15 May 1970
TL;DR: In this article, a holographic image recording and reproducing system for use with a conventional television receiver is presented, where a laser beam which is intensity modulated in accordance with video information is projected through a Bragg cell deflection system to provide a scanning image beam.
Abstract: A holographic image recording and reproducing system for use with a conventional television receiver. A laser beam which is intensity modulated in accordance with video information is projected through a Bragg cell deflection system to provide a scanning image beam. The undiffracted output beam from the Bragg diffraction scanning system is employed as the reference beam. The reference beam and the scanning signal beam are converged by an optical lens system at a Fourier transform plane where a light responsive film is transported. Image data from an entire horizontal scanning line of the TV image is overlapped to provide a single holographic image, and a separate deflection mirror or other deflecting system is provided to sweep the scanning signal beam and the reference beam, still converged, slowly across the width of the even more slowly moving film. For playback, the reference beam component is removed, the film is swept by an unmodulated scanning signal beam following the same scanning pattern as the original recording signal beam, and a photodetector is positioned on a projection of the path of the original reference beam to reconstruct the television signal for playback through the TV receiver.

26 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202310
202215
202131
202040
201929
201844