In this work, we review our recent development on nanoultrasonics based on an optical piezoelectric transducer. By embedding strain patterns in piezoelectric nano-layers and by manipulating optical field intensity in temporal and spatial domains, THz nanoacoustic waves with an acoustic wavelength on the order of or shorter than 10 nm can be generated with a nanometer-scaled lateral spot size, much smaller than the excitation optical wavelength. Noninvasive subsurface ultrasonic imaging can thus be realized with a nanometer resolution. © 2007 IEEE.