Signal beam

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

Near field optical storage mask layer, disk, and fabrication method

Abstract: A mask layer for a high-density near-field optical storage system includes nonlinear optical material and nanoparticles embedded in the nonlinear optical material. The mask layer in combination with a data layer is useful for forming an optical disk. One technique for storing data in the optical disk includes using a gate beam to modify an index of refraction in a modified portion of the nonlinear optical material using a signal beam to provide nanoparticle resonance excitation of selected nanoparticles within the modified portion of the nonlinear optical material.

Localized dynamic light scattering system with doppler velocity measuring capability

Abstract: A localized dynamic light scattering measurement system includes a beam displacer for splitting an incident beam having two orthogonal linearly polarized beam components with slightly different frequencies into two orthogonal linearly polarized output beams focused onto an object to be measured. The beam displacer cooperates with an iris to collect and recombine scattering beams each reversely backscattered at 180 degrees from the object so as to form a signal beam, which is polarized by a polarizer to produce two polarization components, thereby generating a heterodyne interference signal associated with the polarization components. A signal processing unit obtains measurement data on the object based on power spectrum or autocorrelation data corresponding to the heterodyne interference signal.

Optical communication system and remote exciting light amplifier module

Abstract: PROBLEM TO BE SOLVED: To provide an optical communication system and a remote exciting light amplifier module, in which high-quality signal beam transmission is performed. SOLUTION: A signal beam that is sent from a certain communication station, is transmitted by an optical transmission line and reaches another communication station. The signal beam is optically amplified by EDFs 161-163 in a relay optical amplifier 100 which is provided in the communication station, and is lost by a variable optical attenuator 170 of which a transmission loss spectrum is variable. The signal beam is also optically amplified by a remote exciting light amplifier module which is provided on the optical transmission line. The transmission loss spectrum of the variable optical attenuator 170 is controlled by a control circuit 200 based on a result of monitoring a level of the signal beam and another result of monitoring (appropriately a result of monitoring a level of monitoring light propagated by a transmission optical fiber for propagating the signal beam). COPYRIGHT: (C)2005,JPO&NCIPI

Slow Light, Stopped Light and Guided Light in Hot Rubidium Vapor Using Off-resonant Interactions

Abstract: This thesis presents the applications of some of the coherent processes in a three-level atomic system, to control spatial and temporal properties of a signal pulse. We use two Raman absorption resonances in rubidium vapor separated by a few MHz to achieve a rapidly tunable slow-light system. We control the slow-light characteristics all-optically by tuning the frequency and power of a coupling beam. A dual absorption slow-light system is known to cause less pulse broadening than a single transmission resonance system, and thus, a tunable double absorption system is advantageous. We use a four-wave mixing process to demonstrate pulse storage in rubidium vapor for times much greater than the pulse width. We demonstrate storage of both the temporal and spatial profile of the pulse. We overcome the diffusion of spatial information during the storage in warm atomic vapor by storing the Fourier transform of the image instead of an image with a flat phase. The Raman absorption resonance is also used to control the transverse refractive index profile of the signal beam. The refractive index of the signal interacting with a coupling beam in a Raman process is dependent on the coupling beam intensity. We use a first order Laguerre-Gaussian (LG01) coupling beam to create a waveguide like transverse refractive index profile. We demonstrate propagation of a focused signal beam for lengths much greater than the Rayleigh length. Finally, we demonstrate a dual absorption atomic prism, which is capable

Forward-Scattering Degenerate Four-Wave Mixing Detection in Micro-Column Liquid Chromatography Using Fused-Silica Capillary Flow Cells

Abstract: In order to have as simple a chromatographic setup as possible, laser-based forward scattering degenerate four-wave mixing (FD4WM) detection is applied directly to fused-silica capillary flow cells that can be used in micro-column liquid chromatography (mu LC). Compared to the previously used specially designed flow cells (optimized from an optical point of view), such cylindrically shaped cells have obvious disadvantages such as background scatter and signal beam distortion. However, a laser beam can be focused easily in a fused-silica capillary, yielding a laser-probed volume of less than 100 pL, which is attractive for miniaturized chromatographic systems. Parameters such as capillary dimensions (internal and outer diameters), capillary configuration in relation to eluent flow direction, flow rate, and various background suppression techniques are considered from a theoretical and a practical point of view and subsequently optimized. Interestingly, the direction of the eluent flow is critical; it should be in the plane formed by the two laser beams. mu LC/F-D4WM is used to analyze spiked river Rhine water.