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.

Compact optical system for pulse-to-pulse laser beam quality measurement and applications in laser machining

Abstract: Fluctuations in beam quality (M2) have been observed on a pulse-to-pulse basis from an industrial Nd:YAG laser. This was achieved with a compact multiplane imaging method incorporating quadratically distorted diffraction gratings, which enabled simultaneous imaging of nine planes on a single CCD array. With this system, we measured across a range of beam qualities with an associated error (in M2 variation) of the order of 0.7%. Application of the system to fiber-optic beam delivery and laser drilling is demonstrated.

A solid-state electro-optic phase modulator for laser Doppler anemometry

Abstract: It is shown how a simple sawtooth phase modulator can be used to shift the frequency of a laser Doppler signal. Such a device permits the determination of velocity sense and aids interpretation of turbulent distributions. These applications are demonstrated, and a null method of velocity determination which can form the basis of a feedback tracking loop is suggested.

Determination of laser beam parameters with the phase space beam analyser

Abstract: The properties of the phase space beam analyser (PSBA), first introduced by Nemes, were investigated theoretically and experimentally. This optical system enables one to measure far-field divergence and beam radius of a laser beam simultaneously. Experiments were performed with a pulsed Nd: YAG laser with stable and unstable resonators and with a HeNe laser in fundamental mode operation. The theoretical description was based on Fresnel integrals, which were solved numerically using a FFT algorithm. The results presented indicate that the PSBA provides a simple means to determine beam quality and to investigate the mode properties of optical resonators, if diffraction effects are properly compensated.

Uniform field-induced strain in a∕b-axes-oriented Bi3.9Pr0.1Ti3O12 thick films on IrO2∕Si substrates for lead-free piezoelectric microdevice applications

Abstract: We grew 1.5-μm-thick Bi3.9Pr0.1Ti3O12 (BPT) polycrystalline films with a∕b-axes orientation on IrO2∕Si substrates from chemical solutions and measured electric-field-induced strain e by a double-beam laser doppler vibrometer and atomic-force microscopy (AFM). The results reflected uniform film growth and elimination of elastic deformation of the substrate, and the microscopic piezoelectric response in AFM measurements agreed well with the macroscopic response evaluated by laser vibrometer. A large longitudinal e=0.3% was observed at 400kV∕cm and 10Hz, and the piezoelectric coefficient d33=de∕dE∣0=60pm∕V was calculated. X-ray diffraction analyses revealed that the (200)∕(020) peak of BPT was comprised of 40% a domain and led to the reduced values of ferroelectric polarizations of 2Pr=35 and Psat=23μC∕cm2. This suggests that applying an electric field did not cause fraction reconfiguration of a- and b-domains, and, therefore, the measured large strain was achieved without contribution from the 90°-domain-wa...