Topic
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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TL;DR: In this article, the dynamical theory of diffraction is applied to the reconstruction process in a thick hologram grating, and the intensity of the diffracted wave is equal to that predicted by the coupled wave theory.
Abstract: The dynamical theory of diffraction is applied to the reconstruction process in a thick hologram grating Variations in both dielectric constant and absorption are considered, and slant of the fringes is taken into account It is found that the intensity of the diffracted wave is equal to that predicted by the coupled wave theory The phase of the signal beam and its direction of propagation after it emerges from the holographic medium when the Bragg condition is not satisfied are discussed
12 citations
TL;DR: The measured size of the smallest resolvable element of this imaging system is consistent with the value predicted by an improved model that considers the combined image blurring effect due to finite pump beam size, thick nonlinear crystal, and polychromatic infrared illumination.
Abstract: To the best of our knowledge, we present the first demonstration of short-wavelength infrared image upconversion that employs intense picosecond signal and pump beams. We use a fiber laser that emits a signal beam at 1877 nm and a pump beam at 1550 nm-both with a pulse width of 1 ps and a pulse repetition rate of 21.7 MHz. Due to synchronization of high peak-power pulses, efficient upconversion is achieved in a single-pass setup that employs a bulk lithium niobate crystal. Optimizing the temporal overlap of the pulses for high upconversion efficiency enables us to exploit a relatively large pump beam diameter to upconvert a wider range of signal spatial frequencies in the crystal. The 1877 nm signal is converted into 849 nm-enabling an image to be acquired by a silicon CCD camera. The measured size of the smallest resolvable element of this imaging system is consistent with the value predicted by an improved model that considers the combined image blurring effect due to finite pump beam size, thick nonlinear crystal, and polychromatic infrared illumination.
12 citations
TL;DR: In this paper, an on-chip all-optical dynamic tuning scheme for coupled nonlinear resonators employing a single control beam injected in parallel with a signal beam was proposed.
Abstract: We propose and analyze an on-chip all-optical dynamic tuning scheme for coupled nonlinear resonators employing a single control beam injected in parallel with a signal beam. We show that the nonlinear Kerr response can be used to dynamically switch the spectral properties between a “dark state” and electromagnetically induced transparency configurations. Such a scheme can be realized in integrated optical applications for pulse trapping and delaying.
12 citations
TL;DR: In this paper, the optical properties of solid samples of polymethyl-methacrylate doped with fulgide photochromic molecules were studied and the transmittance of a thin plate sample was measured when both the activation (UV) and bleaching wavelengths are employed.
12 citations
Patent•
08 Apr 1976TL;DR: In this article, an interferometer that simultaneously employs two phase-quadrature reference beams of coherent light which interfere with a signal beam reflected from a spot of a displaceable signal mirror insonified by an ultrasonic wave is presented.
Abstract: An interferometer, that simultaneously employs two phase-quadrature reference beams of coherent light which interfere with a signal beam of coherent light reflected from a spot of a displaceable signal mirror insonified by an ultrasonic wave, permits an output signal to be derived which is proportional to the sum of the squares of the ultrasonic frequency component of the interference between the signal beam and each respective one of the reference beams. This output signal is inherently substantially proportional to the intensity of the ultrasonic wave then insonifying the spot of the signal mirror and independent of random phase drift and environmental vibrations in the interferometer. The interferometric technique of the present invention, which permits the ultrasonic wave to be in the form of pulse bursts of only a few cycles so that the output signal can be range-gated, is suitable for use in an ultrasonic-wave measurement and image display system.
12 citations