基于声光折射的聚焦超声焦点声压检测

提出了一种基于声光折射对聚焦超声焦点声压进行非侵入式检测的方法。当一束直径小于声波长的平行光束入射穿过聚焦超声的焦点时,通过研究焦点声压与光线偏转的具体关系,建立了光线最大偏转距离与焦点声压变化的关系模型,从而计算出焦点峰值声压。为了对理论模型进行验证,采用凹球面型聚焦换能器进行实验研究。通过与采用光纤水听器测量的结果进行对比,证明理论模型的可行性。结果表明实验得到的光斑图像与理论分析的结果一致,且用该方法测得的焦点峰值声压与光纤水听器测量的结果相比,相对误差小于15%,证明该方法具有可行性,能够定量检测焦点峰值声压。模型的提出也为将声光折射效应用于整个聚焦声场的定量检测提供了实验依据和理论依据。

Measurement of Acoustic Pressure of the Focused Ultrasound at Focus Based on Acousto-Optic Refraction

Based on acousto-optic refraction, a non-invasive method used for detecting acoustic pressure of the focus of focused ultrasound is proposed. By studying the specific relationship between acoustic pressure of the focus and the ray deflection when a parallel beam whose diameter is less than the wavelength of the sound wave is crossing the focus of the focused ultrasound, a relational model between the maximum deflection distance of the ray and the change of the focus acoustic pressure is established, thus the peak acoustic pressure of the focus is calculated. In order to verify the theoretical model, the concave sphere type focused transducers are used for experiment research. By comparing with the result measured by optical fiber hydrophone, the feasibility of the theoretical model is proved. The results show that the facula images acquired in experiment are consistent with the results of theoretical analysis, and the relative error between the acoustic pressure of the focus measured by current method and that by using optical fiber hydrophone is less than 15%, which proves the feasibility of the method. And it can be used to detect the peak acoustic pressure of the focus quantificationally. The proposition of this model provides the experimental and theoretical evidence for that the acousto-optic refraction effect can be used to measure the whole focused ultrasound field quantificationally.