Surface-guided acoustic waves

Better sensitivity has been reported (32,33) with a surface guided wave, known as a Love wave. A shear horizontal wave is directed along the surface on top of the device a layer is deposited in which the acoustic waves are carried at a lower velocity. 

Rayleigh wave - A guided elastic wave along the surface of a solid also called surface acoustic wave. 

Josse F., Bender F., and Cernosek R. W., Guided shear horizontal surface acoustic wave sensors for chemical and biochemical detection in liquids, Anal. Chem., 73,5937-5944, 2001. 

Li Z., Guided shear horizontal surface acoustic wave (SH-wave) chemical sensors for detection of organic contaminants in aqueous environments, PhD Marquette University, 2005. 

Li Z., Jones Y., Hossenlopp J., Cernosek R., and Josse R, Analysis of liquid-phase chemical detection using guided shear horizontal-surface acoustic wave sensors. Anal. Ghent., 77, 4595-4603, 2005. 

Ultrasonic transducers can excite various wave modes, eg, guided Lamb waves that may be suitable for specific apphcations (143). Ultrasonic excitation is also used to detect the so-called acoustic nonlinearity associated with defects, eg, in PMC (144,145). The combination of recording guided ultrasonic waves with numerical back-calculation of wave propagation for detecting indications of defects in PMC pipes also looks promising (146). Surface-bonded fiber optics can detect ultrasonic waves via interferometric techniques (147). Beyond frequencies of 1 GHz, ultrasonics is called acoustic microscopy, for details, the reader is referred to Reference 148. This technique can be applied to polymers or PMC (149), specifically to polymeric microelectronics packaging (150). 

FIGURE 3.20 Schematic drawing of a guided-wave acousto-optic Bragg deflector, using two tilted surface acoustic waves. 

Kuhn, L., Dakss, M.L., Heidrich, P.F., and Scott, B.A. 1970. Deflection of an optical guided wave by a surface acoustic wave. Appl. Phys. Lett. 17 265. 

Nguyen, L.T. and Tsai, C.S. 1977. Efficient wideband guided-wave acoustooptic Bragg diffraction using phased surface acoustic wave array in LiNbOs waveguides. Appl. Opt. 16 1297-1304. 

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