Traditional acousto-optic (AO) devices based on bulk crystal materials have weak energy confinement abilities for both photons and phonons, leading to a low AO interaction strength. Compared with bulk materials, photonic integrated circuits (PICs) allow surface acoustic waves (SAWs) to be well confined within the thin film used to disturb the guided light waves, exhibiting a high energy overlap within the wavelength scale.
Click here for original story, Highly efficient acousto-optic modulation using non-suspended thin-film lithium niobate-chalcogenide hybrid waveguides
Source: Phys.org