Refractive index modulation in lithium niobate slab using lamb wave
Refractive index modulation in Y-X Lithium Niobate slab through GHz Lamb wave is theoretically analyzed. Dispersion curves and generated displacement field pattern for acoustic waves in slab have been calculated using Rayleigh-Lamb frequency relations and the displacement potentials techniques respectively. Variation in refractive index of slab due to mechanical strain generated by Lamb wave is estimated using photo-elastic effect. It is found that the maximum change in refractive index for S0 mode at 5 GHz of acoustic frequency is 0.027 along X-direction of wave propagation and 0.012 along Y-transverse polarization of wave.