Signal beam

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

Generation of Airy beams by four-wave mixing in Rubidium vapor cell.

Abstract: We report on an experimental generation of Airy beams by four-wave mixing (FWM) in atomic vapor cells This is achieved by using a non-degenerate FWM process, which occurs with two Gaussian pump beams and one Airy signal beam in hot Rubidium vapor After satisfying the phase matching condition, a FWM field with the profile of an Airy beam can be generated In our experiment, the diffraction-free and self-healing behaviors of the generated FWM beam are examined The results shown that the generated FWM beam is an Airy beam The nonlinear generation process can be extended to other configurations in the atomic medium, which will be useful for manipulation and application of Airy beams in atomic systems

Image projection device with suppressed moire

Abstract: The invention relates to an image projection device. This device comprises an illumination system having a lamp for supplying an illumination beam, at least one image display panel for modulating the illumination beam in accordance with an image to be projected to a signal beam, and a projection lens system for projecting the image on a projection screen. To suppress Moire interference between the structure of the image projection screen and the image display panel, an optically transparent beam-displacing element is arranged at an angle with respect to the signal beam axis in at least a portion of the signal beam in the light path between the image display panel and the projection screen at a position where a lamp image is present.

Apparatus for measuring surface movement of an object that is subjected to external vibrations

Abstract: A system for non-destructively measuring an object and controlling industrial processes in response to the measurement is disclosed in which an impulse laser generates a plurality of sound waves over timed increments in an object. A polarizing interferometer is used to measure surface movement of the object caused by the sound waves and sensed by phase shifts in the signal beam. A photon multiplier senses the phase shift and develops an electrical signal. A signal conditioning arrangement modifies the electrical signals to generate an average signal correlated to the sound waves which in turn is correlated to a physical or metallurgical property of the object, such as temperature, which property may then be used to control the process. External, random vibrations of the workpiece are utilized to develop discernible signals which can be sensed in the interferometer by only one photon multiplier. In addition the interferometer includes an arrangement for optimizing its sensitivity so that movement attributed to various waves can be detected in opaque objects. The interferometer also includes a mechanism for sensing objects with rough surfaces which produce speckle light patterns. Finally the interferometer per se, with the addition of a second photon multiplier is capable of accurately recording beam length distance differences with only one reading.

Hybrid laser power combining and beam cleanup system using nonlinear and adaptive optical wavefront compensation

Abstract: An optical amplification system directs a diffraction-limited signal beam through a series of approximately 90° crossings with a number of non-diffraction-limited pump beams in a photorefractive medium All of the beams are s-polarized, resulting in an energy transfer from the pumps to the signal beam while leaving the signal beam diffraction-limited The photorefractive medium is preferably a series of BaTiO 3 :Rh crystals that receive the pump and signal beams through orthogonal faces, with their C-axes at approximately 45° to both beams A binary tree optical distribution network is used to minimize waveguide splits in forming a large number of pump beams The outputs of several amplification modules are combined into a single output beam using adaptive optics, with the outputs from the different modules phase matched to each other by diverting two minor portions of the combined beam, partially overlapping the diverted beams and adjusting the amplification module phases to cancel phase differentials between the overlapped portions Similarly, sets of combined and phase-matched beams can be combined with each other (again using adaptive optics) to generate still higher powers using a super module approach