An acoustic probe includes an acoustic transducer having acoustic transducer elements arranged in a one-dimensional array; and a variably-refracting acoustic lens coupled to the acoustic transducer. The variably-refracting acoustic lens has a pair of electrodes configured to adjust the focus of the variably-refracting acoustic lens in response to a selected voltage applied across the electrodes. In one embodiment, the variably-refracting acoustic lens includes a cavity, first and second fluid media disposed within the cavity, and the pair of electrodes. The speed of sound of an acoustic wave in the first fluid medium is different than the speed of sound of the acoustic wave in the second fluid medium. The first and second fluid media are immiscible with respect to each other, and the first fluid medium has a substantially different electrical conductivity than the second fluid medium.