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Laser Doppler vibrometer

About: Laser Doppler vibrometer is a research topic. Over the lifetime, 6319 publications have been published within this topic receiving 76068 citations.


Papers
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Journal ArticleDOI
TL;DR: The proposed non-contact hybrid system can effectively characterize the dispersive relation without knowledge of neither the materials characteristics nor the mathematical model and proved a high sensitivity of the air-coupled and laser ultrasound in characterizing Lamb wave dispersion in plate-like structures.

52 citations

Journal ArticleDOI
TL;DR: In this article, the authors demonstrated the generation of a highly coherent x-ray laser at 13.9 nm by an oscillator-amplifier configuration with two targets, and the observed divergence is close to the diffraction limited value, and this beam has full spatial coherence.
Abstract: We have demonstrated the generation of a highly coherent x-ray laser at 13.9 nm by an oscillator-amplifier configuration with two targets. In the oscillator-amplifier configuration, a seed x-ray laser beam from one target is injected into a plasma amplifier at another target. When the propagation of the x-ray laser beam is not affected by refraction in the amplifier, a highly coherent x-ray laser beam with small divergence of 0.2 mrad is generated. The observed divergence is close to the diffraction limited value, and this beam has full spatial coherence.

52 citations

Patent
06 Sep 1995
TL;DR: In this article, a method for generating at least three laser beams of different wavelengths for displaying color video pictures, a pulsed laser is used to generate light, which is released in a pulse and is introduced into a medium with nonlinear optical characteristics for generating a laser beam.
Abstract: In a process for generating at least three laser beams of different wavelengths for displaying color video pictures, a pulsed laser is used to generate light. The light output of the pulsed laser is released in a pulse and is introduced into a medium with nonlinear optical characteristics for generating a laser beam. In addition to the laser beam generated by excitation, this medium releases an additional laser beam whose frequency is given by the sum or difference frequencies of the exciting laser beam and the excited laser beam due to the nonlinear optical characteristics of the medium. The laser beams generated by the medium in this way and the exciting laser beam are used directly, or after frequency conversion, to display monochromatic partial images of a color video picture. An apparatus according to the invention contains suitable devices for carrying out the process.

52 citations

Patent
Sung-Ha Kim1, Dho Sang-Whoe1
04 Feb 2009
TL;DR: In this article, an illumination system is proposed to remove laser speckle and a projection system including the same, which includes a light source having at least one laser, a diffractive optical element to divide a laser beam emitted from the laser light source into a plurality of sub-beams and periodically move in such a way as to temporally average the laser beam.
Abstract: An illumination system designed to remove laser speckle and a projection system including the same. The illumination system includes a laser light source having at least one laser, a diffractive optical element to divide a laser beam emitted from the laser light source into a plurality of sub-beams and to periodically move in such a way as to temporally average the speckle of the laser beam, and an optical fiber bundle including a plurality of fibers with the same length to divide the sub-beams into smaller sub-beams. The illumination system divides the laser beam emitted from the laser light source into sub-beams and temporally or spatially averages the sub-beams, thereby effectively reducing or removing laser speckle. The projection system employing the illumination system can provide improved image quality.

52 citations

Proceedings ArticleDOI
17 Jun 2012
TL;DR: In this paper, a new contactless radar based vibration measurement technique is presented, which features an RF frontend based on a passive six-port interferometer working at 24 GHz.
Abstract: Displacement detection and vibration measurements are important requirements for automation and mechanical stress diagnosis in diverse industrial environments. Laser interferometry is a widely used technique for these kinds of measurements since it features high-resolution, wide dynamic range and wide frequency response. Another advantage of the laser interferometry technique is contactless diagnosis/sensing which allows remote operations. However this technique is not suitable in harsh environments for instance with the presence of dust or fog which occur in several industrial production sites. In this paper a new contactless radar based vibration measurement technique is presented. It features an RF frontend based on a passive six-port interferometer working at 24 GHz. A dedicated signal processing unit is also presented. The proposed hardware allows to measure with a position accuracy of 0.5 µm.

52 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202381
2022177
2021122
2020142
2019134
2018174