Surface acoustic waves are very effective for the inspection of cracks and other defects in near-field region of the sample. Surface acoustic waves were generated by illumination of a sample surface with a Q-switched Nd:YAG laser pulse. A multiple slit and a cylindrical lens were used to generate the tone-burst like surface waves. Non contact detection of laser-generated surface acoustic waves was performed with the fiber optic Sagnac interferometer on a carbon steel specimen. Rayleigh wave velocity was obtained by the cross correlation of the signals recorded at different location, and was used to estimate the predominant frequency of the surface wave. Adjustment of the center frequency of the surface wave was performed by changing the distance between the sample and the lens, and the proper range for narrowband frequency was discussed.