This paper presents a characterization of ultrasonic generation from the sidewall of an optical fiber. Ultrasonic generation from an optical fiber could have broad applications, such as ultrasonic imaging, ultrasonic nondestructive test (NDT), and acoustic pyrometers and so on. There are many advantages of these fiber-optic ultrasonic transducers, such as small size, light weight, ease of use, and immunity to electromagnetic interference. This paper discusses two main factors that will influence the signal strength generated by the sidewall of the ultrasonic generator. The two factors are the thickness of the photoabsorption material and the optical energy emitted from the sidewall fiber. A 20 mm length fiber-optic sidewall ultrasonic generator was used for the characterization. Gold-nanocomposite materials were used as the photoabsorption material. A hydrophone was used to detect the ultrasonic signal. The ultrasonic time and frequency profile and the ultrasonic field distribution at the longitudinal section of this fiber-optic sidewall ultrasonic generator have been characterized in this paper.
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