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A Simple Model for Nonlinear Confocal Ultrasonic Beams |
| ZHANG Dong;ZHOU Lin;SI Li-Sheng;GONG Xiu-Fen |
| Institute of Acoustics, Key Lab of Modern Acoustics, Nanjing University, Nanjing 210093 |
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| Cite this article: |
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ZHANG Dong, ZHOU Lin, SI Li-Sheng et al 2007 Chin. Phys. Lett. 24 131-134 |
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Abstract A confocally and coaxially arranged pair of focused transmitter and receiver represents one of the best geometries for medical ultrasonic imaging and non-invasive detection. We develop a simple theoretical model for describing the nonlinear propagation of a confocal ultrasonic beam in biological tissues. On the basis of the parabolic approximation and quasi-linear approximation, the nonlinear Khokhlov--Zabolotskaya--Kuznetsov (KZK) equation is solved by using the angular spectrum approach. Gaussian superposition technique is applied to simplify the solution, and an analytical solution for the second harmonics in the confocal ultrasonic beam is presented. Measurements are performed to examine the validity of the theoretical model. This model provides a preliminary model for acoustic nonlinear microscopy.
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| Keywords:
43.25.+y
43.80.+p
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Published: 01 January 2007
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