The use of coherent light from laser sources has revolutionized the capabilities of measurement techniques in experimental fluid mechanics. In particular, laser Doppler velocimetry has become a standard tool for measuring nonintrusively the small-scale structure of turbulence in fluids. Similarly, laser vibrometers are becoming common instruments for detecting vibrations on solid surfaces. Interferometric measurements (homodyne or heterodyne) can provide very accurate surface vibration measurements, with resolution of a fraction of an Angstrom; subsequently, they are a powerful tool for monitoring fluid-structure interactions, especially for small scale phenomena. At larger scales, another powerful tool is the laser speckle and holographic interferometry which, when combined with optical Fourier transform techniques, can yield a direct visualization of wave propagation of the ω-k space (wave vector filtering). A recent effort has also been made to design a simple and rugged fiber optic laser probe that would be used to measure noninvasively the vector displacement of a vibrating structure. Such a probe allows the identification of both in-plane (short wavelength, acoustically inefficient) and out-of-plane (long wavelength, acoustically efficient) modes of vibration, and the conversion between these modes at discontinuities such as ribs on the surface. The relation between such vector measurements with acoustical holography and structural intensity will be discussed together with the use of scanning techniques. [Work supported by ONR.]