Atypical Applications for Gas-coupled Laser Acoustic Detection

3rd International Symposium on Laser Ultrasonics and Advanced Sensing

Caron, J.N.^1,2 ; Kunapareddy, P.^1

Research Support Instruments, 4325-B Forbes Boulevard, Lanham, 20706 MD, United States^1

Quarktet, Silver Spring, MD 20901, United States^2

关键词: Detection characteristics;    Directivity pattern;    Index of refraction;    Laser-generated ultrasound;    Orders of magnitude;    Ultrasound amplitude;    Ultrasound propagation;    Ultrasound scanning;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/520/1/012022/pdf
DOI  :  10.1088/1742-6596/520/1/012022

来源: IOP

【 摘 要 】

Gas-coupled laser acoustic detection (GCLAD) was primarily developed to sense laser-generated ultrasound in composite materials. In a typical setup, a laser beam is directed parallel to the material surface. Radiated ultrasound waves deflect or displace the probe beam resulting from changes in the air's index of refraction. A position-sensitive photodetector senses the beam movement, and produces a signal proportional to the ultrasound wave. In this paper, we discuss three applications of GCLAD that take advantage of the unique detection characteristics. Directivity patterns of ultrasound amplitude in water demonstrate the use of GCLAD as a directional hydrophone. We also demonstrate the sensing of waveforms from a gelatin. The gelatin mimics ultrasound propagation through skin tissues. Lastly, we show how GCLAD can be used as a line receiver for continuous laser generation of ultrasound. CLGU may enable ultrasound scanning at rates that are orders of magnitude faster than current methods.