武汉光电论坛第130期

报告题目：使用微环谐振器和激光产生的超声聚焦的超声检测和成像

Ultrasound Detection and Imaging Using Microring Resonators and Laser Generated Focused Ultrasound

时 间：2017年7月19日10:00-12:00

地 点：光电国家实验室A301

报 告 人：Prof. L. Jay Guo，美国密西根大学

邀 请 人：光电子器件与集成功能实验室

报告人简介：

L. Jay Guo于1999年在密西根大学开始学术生涯，2011年起担任电子工程与计算机科学系教授，同时受聘于应用物理系、机械工程系和大分子科学与工程系。他发表超过200篇期刊论文，被引用超过25,000次，拥有近20项美国专利。他实验室已发表的很多工作被大量媒体报道。他曾获得密西根大学工学院优秀研究奖和电子与计算机科学系杰出成就奖。他团队的研究方向包括基于聚合物的光子器件与传感器应用，有机与混合光伏，等离子体纳米光子学，纳米压印和卷对卷纳米制造技术。

Biography:

L. Jay Guo is currently a Full Professor at the Department of Electrical Engineering and Computer Science, University of Michigan. L. Jay Guo started his academic career at the University of Michigan in 1999, and has been a full professor of Electrical Engineering and Computer Science since 2011, and affiliated with Applied Physics, Mechanical Engineering, Macromolecular Science and Engineering. He has more than 200 refereed journal publications with over 25,000 citations, and close to 20 US patents. Many published work from his lab have been featured by numerous media. He was the recipient of the Research Excellence Award from the College of Engineering at UM and Outstanding Achievement Award from the EECS department. His group’s researches include polymer-based photonic devices and sensor applications, organic and hybrid photovoltaics, plasmonic nanophotonics, nanoimprint-based and roll to roll nanomanufacturing technologies.

报告摘要：

超声的光学检测是基于应变场与光场的相互作用的新兴技术，调节谐振腔的光学特性以进行高灵敏检测。与传统的压电换能器相比，这种检测方案具有几个独特的优点，例如宽频带响应，以及灵敏度与尺寸无关。检测器的高灵敏度对于较深的穿透深度至关重要，特别是对于高分辨率成像，因为对高频超声波有强衰减。此外，小器件尺寸具有在超声检测中实现宽接受角的优势。我将介绍基于聚合物光子微环谐振器的超声波高灵敏度和宽带检测，并展示其在高分辨率光声层析与光声显微技术中的应用。类似原理还可应用于太赫兹检测，微环可以“听到”吸收太赫兹能量的纳米材料产生的声波。我还将介绍产生和聚焦超声波的薄膜光学发射器，用于强振幅聚焦超声成像与治疗应用。光声源由碳纳米管和弹性体聚合物制成。纳米复合材料作为优异的光吸收器和高效的热转化器，可以产生具有强振幅的输出压力，并具有显示出高频特性的对应频谱。这种方法可以为收集和图形化等细胞工程提供多功能的工具，更重要的是，非热破坏裂可以促进靶向细胞的药物输运与基因治疗。我将讨论最近使用光声透镜的高度聚焦的强振幅超声波来展示确定性微泡生成的实验。

Abstract:

Optical detection of ultrasound is an emerging technique based on the interaction of strain field and optical field, modulating the optical properties of the resonance cavity for sensitive detection. Such a detection scheme can have several unique advantages, such as broadband response and size-independent sensitivity, compared with conventional piezoelectric transducers. Detector’s high sensitivity is essential for deep penetration depth, especially for high-resolution imaging because of the strong attenuation of high-frequency ultrasound. Besides, small element size has the advantage of realizing wide acceptance angle of ultrasound detection. I will describe highly sensitive and broad band detection of ultrasound by polymer photonic microring resonators, and demonstrate its application for high resolution photoacoustic tomography and photoacoustic microscopy. Similar principle can be applied to THz detection, where the microring can “listen to” the sound wave generated by the nano-material absorbing the THz energy. I will also present thin-film optical transmitters to generate and focus the ultrasound, targeting high-amplitude focused ultrasound for imaging and therapeutic applications. The optoacoustic sources are made of carbon-nanotubes (CNTs) and elastomeric polymers. As the nano-composite works as excellent optical absorbers and efficient heat converters, output pressure with strong amplitudes can be generated and has a corresponding frequency spectrum showing high-frequency characteristics. This approach could provide a versatile tool for cell engineering in terms of harvesting and patterning, and more importantly, non-thermal disruption to facilitate drug delivery and gene therapy for targeted cells. I will discuss recent experiment showing deterministic microbubble generation by highly focused high amplitude ultrasound using the photoacoustic lens.

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