Suppression of higher harmonic generations of SAW in LiNbO3

ZnO thin-film loading of YZ-LiNbO3 is used to suppress all the harmonic generations of surface acoustic waves (SAW’s) in the substrate. An optical probing technique is used to measure the intensity variations of the harmonics as a function of acoustic power. Only the first-order diffracted light intensity is observed owing to the suppression of higher harmonic generations of SAW’s. This linearization of the first-order diffracted light intensity versus acoustic power is found to be independent of the interaction length (up to 5 mm) and the acoustic power (up to 4.3 W). The attenuation of SAW’s on YZ-LiNbO3 with a 2-μm ZnO layer was measured to be about 5 dB/cm at 325 MHz.