title: Distributed fiber-optic laser-ultrasound generation based on ghost-mode of tilted fiber Bragg gratings.
abstract: Active ultrasonic testing is widely used for medical diagnosis, material characterization and structural health monitoring. Ultrasonic transducer is a key component in active ultrasonic testing. Due to their many advantages such as small size, light weight, and immunity to electromagnetic interference, fiber-optic ultrasonic transducers are particularly attractive for permanent, embedded applications in active ultrasonic testing for structural health monitoring. However, current fiber-optic transducers only allow effective ultrasound generation at a single location of the fiber end. Here we demonstrate a fiber-optic device that can effectively generate ultrasound at multiple, selected locations along a fiber in a controllable manner based on a smart light tapping scheme that only taps out the light of a particular wavelength for laser-ultrasound generation and allow light of longer wavelengths pass by without loss. Such a scheme may also find applications in remote fiber-optic device tuning and quasi-distributed biochemical fiber-optic sensing.
authors.affiliation: Department of Electrical Engineering, University of Nebraska–Lincoln, Lincoln, Nebraska 68588, USA.
authors.forename: Jiajun
authors.initials: J
authors.lastname: Tian
authors.forename: Qi
authors.initials: Q
authors.lastname: Zhang
authors.forename: Ming
authors.initials: M
authors.lastname: Han