Topic
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.
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TL;DR: In this article, the authors used arrays of silicon cantilever beams as microresonator sensors with nanoscale thickness to detect the mass of individual virus particles and demonstrated the detection of a single vaccinia virus particle with an average mass of 9.5 fg.
Abstract: In this letter, we present the microfabrication and application of arrays of silicon cantilever beams as microresonator sensors with nanoscale thickness to detect the mass of individual virus particles. The dimensions of the fabricated cantilever beams were in the range of 4–5 μm in length, 1–2 μm in width and 20–30 nm in thickness. The virus particles we used in the study were vaccinia virus, which is a member of the Poxviridae family and forms the basis of the smallpox vaccine. The frequency spectra of the cantilever beams, due to thermal and ambient noise, were measured using a laser Doppler vibrometer under ambient conditions. The change in resonant frequency as a function of the virus particle mass binding on the cantilever beam surface forms the basis of the detection scheme. We have demonstrated the detection of a single vaccinia virus particle with an average mass of 9.5 fg. These devices can be very useful as components of biosensors for the detection of airborne virus particles.
563 citations
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29 Mar 1995TL;DR: In this article, the authors proposed a method for laser induced breakdown of a material with a pulsed laser beam where the material is characterized by a relationship of fluence breakdown threshold (Fth) versus laser beam pulse width (T) that exhibits an abrupt, rapid, and distinct change or at least a clearly detectable change in slope at a predetermined laser pulse width value.
Abstract: In one aspect the invention provides a method for laser induced breakdown of a material with a pulsed laser beam where the material is characterized by a relationship of fluence breakdown threshold (Fth) versus laser beam pulse width (T) that exhibits an abrupt, rapid, and distinct change or at least a clearly detectable and distinct change in slope at a predetermined laser pulse width value. The method comprises generating a beam of laser pulses in which each pulse has a pulse width equal to or less than the predetermined laser pulse width value. The beam is focused to a point at or beneath the surface of a material where laser induced breakdown is desired. The beam may be used in combination with a mask in the beam path. The beam or mask may be moved in the X, Y and Z directions to produce desired features. The technique can produce features smaller than the spot size and Rayleigh range due to enhanced damage threshold accuracy in the short pulse regime.
472 citations
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TL;DR: The new trends on Laser Doppler Vibrometry (LDV) development are outlined with particular attention to the innovative solutions answering to the most recent technological requirements which are not met by the current systems as discussed by the authors.
427 citations
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TL;DR: In this paper, the results from dynamic live load tests using the non-contact laser Doppler vibrometer (LDV) system with those from two types of contact sensors are compared.
Abstract: This paper compares results from dynamic live load tests using the non-contact laser Doppler vibrometer (LDV) system with those from two types of contact sensors. Bridge girder deflections and vibrations are simultaneously measured using a linear variable differential transducer (LVDT)-cable system (deflection) and geophone sensors (velocity), both attached to the girders, and the LDV, equipped with displacement and velocity signal decoders. Live load tests are performed on a 3-span continuous unit of the 9-span Doremus Avenue Bridge Replacement Project using 5-axle trucks of known weight and configuration. The Doremus Avenue Bridge is a composite steel slab-on-girder construction. Bridge response is compared for two of the 10 girders. Overall, the LDV measurements of deflection and velocity compare very well with those recorded by the contact sensors and may be used as an alternative to the two systems. Other advantages and disadvantages are also highlighted.
397 citations
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TL;DR: In this article, motion magnification has been developed for visualizing exaggerated versions of small displacements with an extension of the methodology to obtain the optical flow to measure displacements, which can be extended to modal identification in structures and the measurement of structural vibrations.
382 citations