레이저 발생 초음파 트랜스듀서의 특성에 관한 연구

Abstract

Study on the Characteristics of a Laser Generated Ultrasound Transducer Han-Moon, Kim

Graduate School Pukyong National University

Abstract

For study on ultrasound generating characteristics, six circular plane LGUTs(Laser Generated Ultrasound Transducers) with diameter mm were fabricated. Those were made of CNT(Carbone nano-tube) and PDMS(polydimethyl-siloxane) coated on PMMA(poly-methylmethacrylate) acrylic substrates. The CNT and PDMS were coated by the filtering/transition method and the spin coating method respectively, and each has three different thickness. The LGUTs were illuminated by a pulse Laser with about 8 ns pulse width and variable power. The ultrasound waves generated by the LGUTs were measured with a needle hydrophone with diameter mm. As the results, the impulsive shock waves with 15 ns of -6 dB pulse width were obtained from all of the transducers. The amplitudes of the waveform were linearly changed with the Laser intensity. However, the waveform were not changed significantly with the thickness of the CNT or PDMS as well as with the axial distance or the lateral position. It was shown that the theoretical consideration using the temperature change on the LGUT surface could estimate the impulsive wave generation.