Velocity measurements of laser-generated ultrasound by using laser arrays and a phase modulated Michelson interferometer

Author

Nakano, Hidetoshi ; Matuda, Youichi ; Nagai, Satoshi

Author_Institution

Nat. Res. Lab. of Metrol., Ibaraki, Japan

Volume

2

fYear

1998

fDate

1998

Firstpage

1247

Abstract

A phase modulated Michelson interferometer for laser ultrasonics is described. The operation point in the interferometer is the minimum intensity of interference patterns. This scheme allows the use of a high power laser to improve the sensitivity without the saturation of a optical detector. Ultrasonic waveforms with amplitude of a few 10 pm have been obtained by using a 2 W laser. For generation, an array of 4 pulsed Nd:YAG lasers is used to excite toneburst ultrasonic echoes. The echo round trip time can be measured precisely by cycle for cycle overlapping. Several experimental results of ultrasonic waveforms are presented

Keywords

laser beam effects; photoacoustic effect; ultrasonic propagation; ultrasonic velocity; 4 pulsed Nd:YAG lasers; YAG:Nd; YAl5O12:Nd; cycle overlapping; echo round trip time; high power laser; interference patterns; laser arrays; laser-generated ultrasound; optical detector; phase modulated Michelson interferometer; saturation; sensitivity; toneburst ultrasonic echoes; velocity measurements; Interference; Laser excitation; Optical arrays; Optical detectors; Optical interferometry; Optical pulse generation; Phase modulation; Power lasers; Ultrasonic imaging; Velocity measurement;

fLanguage

English

Publisher

ieee

Conference_Titel

Ultrasonics Symposium, 1998. Proceedings., 1998 IEEE

Conference_Location

Sendai

ISSN

1051-0117

Print_ISBN

0-7803-4095-7

Type

conf

DOI

10.1109/ULTSYM.1998.765065

Filename

765065