Ken NAKANO,¹ Kazuhiro HANE,² Shigeru OKUMA¹ and Tadashi EGUCHI³

¹Department of Electrical Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-01 Japan, ²Department of Mechatronics and Precision Engineering, Tohoku University, Aza Aoba, Aramaki, Aoba-ku, Sendai, 980-77 Japan, ³Canon Inc., 3-30-2, Shimo-maruko, Ohta-ku, Tokyo, 146 Japan

(Received August 28, 1996; Accepted December 6, 1996)

A stroboscopic phase-shift interferometry has been developed to visualize surface acoustic wave (SAW) propagation on SAW devices quantitatively. The developed interferometry is a Fizeau-type one with a multi-mode semiconductor laser diode and an optical isolator. With the laser light illuminating stroboscopically, observed interference intensity gives information about average displacements of the vibrations. Fifty MHz SAW propagation on the surface of the SAW device has been measured with the interferometry. Distribution of the SAW along the propagation path has been observed, whose amplitude is 3 nm (p-p). Repetition accuracy evaluated with the root mean square method is 1/2500 of the laser wavelength. The system is useful for estimating and improving performances of micro-devices.

Key words : surface acoustic wave, surface acoustic wave device, phase-shift interferometry, laser, stroboscopic method, vibration measurement

*Presented at 1996 International Workshop on Interferometory (IWI '96), August 27-29, Wako, Saitama, Japan.