Signal beam

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

Hologram recording device

Abstract: A hologram recording device records hologram in a hologram recording medium by splitting a coherent beam outputted from a beam source into a signal beam and a reference beam, irradiating the hologram recording medium with the signal beam by modulating the signal beam by a spatial light modulator, and by irradiating the hologram recording medium with the other reference beam to have the reference beam overlap the signal beam. The hologram recording device is provided with a plurality of optical elements (20p, 20p’) which can be in two statuses, i.e., in on-mode wherein the reference beam is transmitted or reflected in a prescribed direction toward the hologram recording medium, and in off-mode where the reference beam is guided outside the prescribed direction or blocked. Each of the optical elements (20p, 20p’) is provided with an optical phase modulating means which generates prescribed phase differences (0, π), and a phase modulation control means which controls each of the optical elements (20p, 20p’) to be in the on-mode or off-mode and modulates the reference beam to a beam having a prescribed phase pattern.

Surface inspection with scanned focused light beams

Abstract: A surface inspection system uses a highly focused spot of light moved rapidly over the surface to perform an inspection This permits a ready location of the defects, gives some indication as to their size, and permits a high resolution inspection to be performed in a relatively short time An optical arrangement is employed in which a scanned beam is brought back through the same lens system used in generating the scan to produce an immobilized return signal beam A stop or spatial filter is used on the return beam to permit only the light scattered from defects to reach a detector

Angle-independent continuous wave doppler device

Abstract: An apparatus (10) for determining the velocity of a fluid flowing through a lumen comprises a first diffraction grating transducer (DGT) (1) responsive to a continuous wave (CW) input and operable in a first mode for producing a first signal beam at a first frequency and first phase, and in a second mode for producing a second signal beam at the first frequency and a first phase; and in a second mode for oproducing a second signal beam at a first frequency and a second phase; a second diffraction grating transducer (DGT) (2) operating as a receiver and coupled to the first diffraction grating transducer at a predetermined angle, the second diffraction grating transducer producing a first beam which intersects the first DGT first beam for receiving a first reflected signal associated with the first signal beam, and for producing a second beam which intersects the first DGT second beam for receiving a second reflected signal associated with the second signal beam.

Independent space variables for small-signal electron beam analyses

Abstract: This paper gives a systematic account of three systems of independent space variables useful in small signal electron beam analyses--the familiar Eulerian, polarization, and hose systems. The continuity, dynamical, and power exchange equations are given for each of the three sets of variables, and the relative merits of each system are discussed. The inapplicability of the Lagrangian system to small signal beam problems is also indicated.

Investigation of two-beam-pumped noncollinear optical parametric chirped-pulse amplification for the generation of few-cycle light pulses

Abstract: We demonstrate a new and compact ϕ-plane-pumped non-collinear optical parametric chirped-pulse amplification (NOPCPA) scheme for broadband pulse amplification, which is based on two-beam-pumping (TBP) at 532 nm. We employ type-I phase-matching in a 5 mm long BBO crystal with moderate pump intensities to preserve the temporal pulse contrast. Amplification and compression of the signal pulse from 675 nm - 970 nm is demonstrated, which results in the generation of 7.1-fs light pulses containing 0.35 mJ energy. In this context, we investigate the pump-to-signal energy conversion efficiency for TBP-NOPCPA and outline details for few-cycle pulse characterization. Furthermore, it is verified, that the interference at the intersection of the two pump beams does not degrade the signal beam spatial profile. It is theoretically shown that the accumulated OPA phase partially compensates for wave-vector mismatch and leads to extended broadband amplification. The experimental outcome is supported by numerical split-step simulations of the parametric signal gain, including pump depletion and parametric fluorescence.