Systems and devices are provided for generating focused ultrasound pulses based on a transducer assembly having a piezoelectric layer coupled to an acoustic lens. In some example embodiments, the piezoelectric layer is a composite piezoelectric material having an acoustic impedance configured to match the acoustic impedance of the acoustic lens. The acoustic lens may be formed from aluminum, or an alloy thereof, and may have a distal surface having a non-spherical profile for producing a focal region that is smaller than an equivalent spherical lens. The acoustic lens may have an f-number less than unity. In some embodiments, the acoustic lens is coated with a polymer acoustic impedance matching layer that is compatible with deposition via chemical vapor deposition, such as a p-xylylene based polymer. In some embodiments, the acoustic lens is formed from aluminum or an alloy thereof, and the polymer acoustic impedance matching layer is a Parylene layer.
