TY - JOUR
T1 - Generation and directivity control of bulk acoustic waves by phase velocity scanning of laser interference fringes
AU - Nishino, Hideo
AU - Tsukahara, Yusuke
AU - Cho, Hideo
AU - Nagata, Yoshihiko
AU - Koda, Toshio
AU - Yamanaka, Kazushi
PY - 1995/5
Y1 - 1995/5
N2 - A novel method for generating high-frequency bulk acoustic waves (BAW) using scanning interference fringes (SIF) is presented. The SIF are produced by intersecting two coherent laser beams with different frequencies on an opaque specimen. It is possible to generate unidirectional BAW which propagate into the specimen by this method. Propagation direction of the BAW is determined by the phase-matching condition between the SIF and the wave front of the BAW at the surface, which could be controlled by incident angles of laser beams. The principle of this method and experimental verification using a sintered Si3N4 specimen are described. Experiments were carried out using a 15 mJ/130 ns Q-switched Nd:YAG laser for 80 MHz BAW generation and optical knife-edge method with 50 mW argon-ion CW laser for detection. Directivity of BAW was steered from 24.5° to 77.5° by changing the incident angles of the laser beams from 0.066° to 0.136°. BAW were found to be well collimated especially in the near field.
AB - A novel method for generating high-frequency bulk acoustic waves (BAW) using scanning interference fringes (SIF) is presented. The SIF are produced by intersecting two coherent laser beams with different frequencies on an opaque specimen. It is possible to generate unidirectional BAW which propagate into the specimen by this method. Propagation direction of the BAW is determined by the phase-matching condition between the SIF and the wave front of the BAW at the surface, which could be controlled by incident angles of laser beams. The principle of this method and experimental verification using a sintered Si3N4 specimen are described. Experiments were carried out using a 15 mJ/130 ns Q-switched Nd:YAG laser for 80 MHz BAW generation and optical knife-edge method with 50 mW argon-ion CW laser for detection. Directivity of BAW was steered from 24.5° to 77.5° by changing the incident angles of the laser beams from 0.066° to 0.136°. BAW were found to be well collimated especially in the near field.
KW - Bulk acoustic waves
KW - Laser-generated ultrasounds
KW - Phase velocity scanning method
KW - Scanning interference fringes
KW - Sintered SiN
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U2 - 10.1143/JJAP.34.2874
DO - 10.1143/JJAP.34.2874
M3 - Article
AN - SCOPUS:0029304607
VL - 34
SP - 2874
EP - 2878
JO - Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes
JF - Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes
SN - 0021-4922
IS - 5S
ER -