A method and system for identifying bonding between a material and tubing. The method may include disposing an acoustic logging tool in a wellbore, wherein the acoustic logging tool comprises a transmitter, a receiver, or a transceiver, broadcasting a shaped signal with the transmitter such that the shaped signal interacts with a boundary of a casing and a material and recording a result signal from the boundary with the receiver. The method may further comprise identifying a cut-off time to be applied to the result signal, transforming the result signal from a time domain to a frequency domain, selecting one or more modes sensitive to a bonding at the boundary between the casing and the material, computing a decay rate of the one or more modes that were selected based at least one or more decay curves, and converting the decay rate to a bonding log.