A sensitivity-enhanced all-optical probe for non-contact laser ultrasonic inspection

Non-contact laser ultrasonic technique has been increasingly implemented for non-destructive inspections in harsh environments, high-temperature fields, and components having complex geometries. However, the poor signal-to-noise ratio and low amplitude of laser generated ultrasonic signals under a t...

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Veröffentlicht in:Applied physics letters 2023-10, Vol.123 (17)
Hauptverfasser: Cheng, Zhongwen, Yu, Jinhao, Long, Bainian, Zeng, Lvming, Ji, Xuanrong
Format: Artikel
Sprache:eng
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Zusammenfassung:Non-contact laser ultrasonic technique has been increasingly implemented for non-destructive inspections in harsh environments, high-temperature fields, and components having complex geometries. However, the poor signal-to-noise ratio and low amplitude of laser generated ultrasonic signals under a thermoelastic regime severely restrict its applications. Here, a sensitivity-enhanced all-optical probe was proposed for laser ultrasonic non-destructive testing. It consists of an optical sensor and an ellipsoidal acoustic cavity, where an optical sensor is placed at one focus of the cavity, and the detection point is set at another focus. The ultrasound signals are focused through the cavity and detected by the optical sensor. Side-by-side comparison experiments were carried out, and the results show that the probe can improve the signal amplitude by about 7.8 times compared to using a traditional optical sensor alone. The probe can make laser ultrasound detect defects with lower laser energy, which is of great significance to improve the efficiency of non-contact defect detection.
ISSN:0003-6951
1077-3118
DOI:10.1063/5.0173995