There is not one textbook. The material will be inspired from various sources. Here is a list of references that sometimes go way beyond what we'll do in class.

For Acoustics, see the book:
Amazon logo Kinsler, Lawrence E. Fundamentals of Acoustics. Wiley, 1999. ISBN: 9780471847892.

For Continuum Mechanics, a decent book is:
Amazon logo Spencer, A. J. M. Continuum Mechanics. Dover Publications, 2004. ISBN: 9780486435947. [Preview with Google Books]

For Optics, the best book is:
Amazon logo Born, Max, and Emil Wolf. Principles of Optics: Electromagnetic Theory of Propagation, Interference and Diffraction of Light. Cambridge University Press, 1999. ISBN: 9780521642224. [Preview with Google Books]

For Radar Imaging, see the review article This resource may not render correctly in a screen reader."A Mathematical Tutorial on Synthetic Aperture Radar" (PDF) by Margaret Cheney as well as her book:
Amazon logo Cheney, Margaret, and Brett Borden. Fundamentals of Radar Imaging. Society for Industrial and Applied Mathematics, 2009. ISBN: 9780898716771. [Preview with Google Books]

For Computerized Tomography, see the book:
Amazon logo Natterer, F., and Frank Wübbeling. Mathematical Methods in Image Reconstruction. Society for Industrial and Applied Mathematics, 2001. ISBN: 9780898714722. [Preview with Google Books]

For Seismology, see the review notes "Mathematics of Reflection Seismology (1995)" by William W. Symes.

For the introductory treatment of Wave Equations, I've used:
Amazon logo Evans, Lawrence C. Partial Differential Equations. American Mathematical Society, 2010. ISBN: 9780821849743. [Preview with Google Books]

Amazon logo Folland, Gerald B. Introduction to Partial Differential Equations. Princeton University Press, 1975. ISBN: 9788120318854.

Amazon logo John, Fritz. Partial Differential Equations. Springer, 2013. ISBN: 9781468493351.

Amazon logo Whitham, Gerald Beresford. Linear and Nonlinear Waves. Wiley-Interscience, 1999. ISBN: 9780471359425.

This resource may not render correctly in a screen reader."Notes on the Algebraic Structure of Wave Equations" (PDF) by Steven Johnson.

For Geometrical Optics, I like "Lectures on Geometrical Optics" by Professor Jeffrey Rauch.

We gave a Summer School on Waves and Imaging in 2011 in Vancouver, Canada. Some of the material listed there will be useful as well.