Parallel detection of amplitude-modulated, ultrasound-modulated optical signals.
Parallel detection of amplitude-modulated, ultrasound-modulated optical signals.
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DOI：
10.1364/ol.35.002633
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发表时间：
2010-08
期刊：
影响因子：
3.6
通讯作者：
Rui Li;Lipei Song;D. Elson;M. Tang
中科院分区：
文献类型：
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作者：
Rui Li;Lipei Song;D. Elson;M. Tang
研究了调幅超声对声光信号的影响。将体模暴露于AM US和绿色激光，并在不同曝光时间下进行散斑对比度的CCD测量。结果表明，当CCD曝光时间为AM周期的几分之一时，AO信号以AM频率振荡，当CCD曝光时间为AM周期的倍数时，AO信号停止振荡。AO信号随着AM频率增加或峰-峰（pk-pk）幅度减小而快速减小。在4 ms曝光时间、250 Hz AM频率和1.27MPa峰-峰声压条件下，AO信号较CW超声增强约30%。信号的增加很可能是由于粒子振荡和由AM US产生的辐射力引起的感应剪切波。
We investigated the effect of amplitude-modulated (AM) ultrasound (US) on acousto-optic (AO) signals. A phantom was exposed to both AM US and a green laser, and CCD measurements of speckle contrast were made with various exposure times. The results show that the AO signal oscillates at the AM frequency when the CCD exposure time is a fraction of the AM period and stops oscillating when the CCD exposure time is a multiple of the AM period. The AO signal decreases quickly as the AM frequency increases or peak-peak (pk-pk) amplitude decreases. With 4ms exposure time, 250Hz AM frequency and 1.27MPa pk-pk acoustic pressure, there is an ~30% increase in the AO signal compared with that of CW US. The increase in the signal is likely to be due to the particle oscillation and the induced shear wave as a result of the radiation force generated by the AM US.