Acoustic scanning microscope

STM and SFM belong to an expanding family of instruments commonly termed Scanning Probe Microscopes (SPMs). Other common members include the magnetic force microscope, the scanning capacitance microscope, and the scanning acoustic microscope. ... 

There are two types of scanning acoustic microscopes. If the illumination and the reception of the acoustic waves are performed by two identical lenses arranged confocally, the SAM is called a transmission SAM. The lens geometry used for transmission imaging is shown schematically in Fig. 41 [93]. 

The scanning acoustic microscope is a powerful new tool for the study of the physical properties of materials and has been successfully used for imaging interior structures and for nondestructive evaluation in materials science and biology. 

Atalar, A., Penetration Depth of the Scanning Acoustic Microscope," IEEE Trans. Sonics Ultrason., Vol. 32, No. 2, 1985, pp. 164-167. 

Block, H., Heygster, G., andBoseck, S., Determination of the OTF of a Reflection Scanning Acoustic Microscope by a Hair Crack in Glass at Different Ultrasonic Frequencies," Optik, Vol.82,1989, pp. 147-154. 

In the following example, scanning acoustic microscopy is combined with optical microscopy to measure intimate contact at the ply interfaces of a [0o/90o/0°]r graphite-PEEK laminate. First, eight holes, 1.5 mm (0.059 in.) in diameter, were drilled into the composite specimen. These holes, shown in Figure 7.12, were used to locate where on the composite specimen the scanning acoustic microscope images were taken. 

Figure 7.13 Typical scanning acoustic microscopic image obtained from a [0/90.0]r APC-2 laminate processed at 370°C with 276 kPa for 50 s...

Lin et al. 1985 Wade and Meyyappan 1987 Wey and Kessler 1989) the insonification is broadcast throughout the specimen, and the detection is by a focused optical probe that measures local surface tilt on the surface of the specimen. But in the scanning acoustic microscope both the illumination and the detection are performed by focusing elements and, since these are focused at the same point, the configuration may be described as confocal. The first con-focal acoustic microscopes worked in transmission and, although this is now of mainly historical interest, the transmission arrangement will be described first because in some respects it is simpler and will serve to introduce some principles. 

An early high-resolution transmission scanning acoustic microscope is illustrated in Fig. 2.3. Two acoustic lenses are mounted facing each other on a common axis, and with a common focal plane. A continuous radio-frequency (r.f.) signal is fed to the transducer on one of the lenses, which converts this to... 

Fig. 2.3. One of the original scanning acoustic microscopes. It worked in transmission, so that it was not necessary to use pulsed waves, and the detected transmitted signal could be used directly to modulate the beam in a cathode ray tube. The slow scan was provided by a small motor driving a lead screw, and the fast scan by a modified loudspeaker coil (Lemons and Quate 1974,1979).

The operation of a transmission scanning acoustic microscope requires the lenses to be set up so that they are accurately confocal. This requires holders that can be moved relative to each other along three axes, with rather fine adjustment, and that are rigid to better than a wavelength even when a specimen is vibrating between them. The separation must first be set. If ro is the radius of curvature of each lens, ciq the aperture radius, and n the refractive index, then the focal planes of the two lenses will coincide when the separation between their front surfaces is... 

Atalar, A. (1985). Penetration depth of the scanning acoustic microscope. IEEE Trans. SU-32,164-7. [210]... 

Atalar, A. (1987). Increasing the sensitivity of the scanning acoustic microscope to anisotropy. IEEE 1987 Ultrasonics Symposium, pp, 791—4. IEEE, New York. [55,250]... 

Briggs, G. A. D. (1988). What can you see with a scanning acoustic microscope (Vas kann man mit dem akustischen Rastermikroskop erfassen ) Vortragsveranstaltung des Arbeitskreises Rastermikroskopie in der Materialprufung 13,105-12. [11]... 

Hammer, R. and Hollis, R. L. (1982). Enhancing micrographs obtained with a scanning acoustic microscope using false-colour encoding. Appl. Phys. Lett. 40, 678-80. [38]... 

Heygster, G., Block, H., Gadomski, A., and Boseck, S. (1990). Modeling of the optical transfer function (OTF) of the scanning acoustic microscope (SAM) and its relation to the other scanning microscopes. Optik 85,89-98. [28, 200]... 

Honda, T. and Ohashi, K. (1990). A new approach for corrosion monitoring by a scanning acoustic microscope. Proceedings of the 11th Corrosion Conference, Florence. (In press.) [207]... 

Kulik, A., Gremaud, G., and Satish, S. (1989). Continuous wave reflection scanning acoustic microscope (SAMCRUW). In Acoustical imaging, Vol. 17 (ed. H. Shimizu, N. Chubachi, and J. Kushibiki), pp. 71-8. Plenum Press, New York. [23,71]... 

Meunier, A., Katz, J. L., Christel, P., and Sedel, L. (1988). A reflection scanning acoustic microscope for bone and bone-biomaterials interface studies. /. Orthopaedic Res. 6, 770-5. [197]... 

Okawai, H., Tanaka, M., Chubachi, N., and Kushibiki, J. (1987). Non-contact simultaneous measurement of thickness and acoustic properties of biological tissue using focused wave in a scanning acoustic microscope. Proc 7th Symp. Ultrasonic Electronics, Kyoto. Jap. J. Appl. Phys. 26 (Suppl. 26-1), 52-4. [164]... 

Peck, S. D. and Briggs, G. A. D. (1986). A scanning acoustic microscope study of the small caries lesion in human enamel. Caries Res. 20, 356-60. [182,184]... 

Quinten, A. and Arnold, W. (1989). Observation of stable crack growth in Al203 ceramics using a scanning acoustic microscope. Mat. Sci. Engng. A122, 15-19. [278]... 

Reinholdtsen, P. and Khuri-Yakub, B. T. (1991). Image processing for a scanning acoustic microscope that measures amplitude and phase. IEEE Trans. UFFC 38, 141-7. [205]... 

Somekh, M. G. (1987). Consequences of resonant surface-wave excitation on contrast in reflection scanning acoustic microscope. IEEE Proc. 134,290-300. [122]... 

Wickramasinghe, H. K. (1979). Contrast and imaging performance in the scanning acoustic microscope. /. Appl. Phys. 50,664—72. [108]... 

Yamanaka, K. and Enomoto, Y. (1982). Observation of surface cracks with scanning acoustic microscope. J. Appl. Phys. 53, 846-50. [257]... 

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