Pérez-López Sergio, Tarrazó-Serrano Daniel, Dolmatov Dimitry O, Rubio Constanza, Candelas Pilar
Centro de Tecnologías Físicas, Universitat Politècnica de València, 46022 València, Spain.
National Research Tomsk Polytechnic University, Tomsk 634050, Russia.
Sensors (Basel). 2020 Nov 29;20(23):6824. doi: 10.3390/s20236824.
Fresnel Zone Plates are planar lenses that can be used to focus ultrasound beams. This kind of acoustic lenses can play a key role in the resolution of ultrasonic NDT systems. In this type of pulse-echo applications, the pulse duration is an important parameter that specifies the axial resolution, and thus, shorter ultrasound pulses provide higher resolutions. However, acoustic lenses exhibit a transient response that should be considered when setting the pulse duration, as pulses shorter than the transient state duration result in degradation in the response of acoustic lenses in terms of focal intensity, focal displacement, and lateral and axial resolutions. In this work, a thorough analysis of the transient response of Fresnel Zone Plates is discussed, demonstrating that the transient state should be considered in order to achieve optimal focusing performance. Theoretical and numerical results are presented, showing very good agreement.
菲涅耳波带片是一种可用于聚焦超声束的平面透镜。这种声学透镜在超声无损检测系统的分辨率方面起着关键作用。在这种脉冲回波应用中，脉冲持续时间是指定轴向分辨率的一个重要参数，因此，较短的超声脉冲可提供更高的分辨率。然而，声学透镜会表现出瞬态响应，在设置脉冲持续时间时应予以考虑，因为短于瞬态持续时间的脉冲会导致声学透镜在焦强度、焦位移以及横向和轴向分辨率方面的响应下降。在这项工作中，对菲涅耳波带片的瞬态响应进行了深入分析，结果表明为了实现最佳聚焦性能，应考虑瞬态状态。给出了理论和数值结果，二者吻合度很高。
