Effects of metallic diaphragms on sensitivity characteristics of an optical ultrasonic sensor and reduction of interrogation time based on wavelength division multiplexing for under-sodium visual inspection

ナトリウム中目視検査において金属膜が光学式超音波センサの感度に与える影響と波長分割多重化法による測定時間の短縮

猿田 晃一   ; 山口 智彦 ; 上田 雅司 

Saruta, Koichi; Yamaguchi, Toshihiko; Ueda, Masashi

We have experimentally examined the effects of the metallic diaphragms on the sensitivity characteristics of an optical ultrasonic sensor and investigated the multiplexed interrogation of the diaphragms based on WDM technique. The experimental results show that the sensitivity can be increased by use of thinner and lighter diaphragms. It has also been found that by taking advantage of the interference of the lamb waves propagating through the diaphragm, the sensitivity can be further enhanced by a factor of approximately 5 to 6 with decreasing diameter. The multiplexed interrogation based on WDM technique has been demonstrated in the case of two wavelengths. From this experimental demonstration, we consider that the interrogation time can be significantly reduced by increasing the number of multiplexed wavelengths.