Surface Plasmon Photoacoustic Imaging of Subsurface Objects

该项目旨在开发一种新型的光声（PA）显微镜系统，该系统将能够映射光学不透明材料中深埋的次表面缺陷。在不透明材料中具有亚100 nm尺寸的地下物体的成像仍然是集成电路可靠性和性能的主要关注点。PA技术联合收割机结合了超声的大穿透深度与光学探头的横向空间分辨率的优点。 然而，PA技术的空间分辨率受到衍射的限制。为了克服这些挑战，提出了一种用于亚波长PA技术的新方法，其通过使用以下各项创建高度局部化的光场和超声场：a）用于光学探针的亚100 nm限制的表面等离子体纳米聚焦，用于激光产生的高频的高灵敏度检测（0.5 - 10 GHz）超声，和B）时间反转声学，用于来自纳米级表面下物体的散射超声场的空间聚焦。该PA系统将为微电子器件中的亚表面缺陷成像提供前所未有的空间分辨率和穿透深度。提出的教育和外展计划旨在激发高中学生追求STEM职业，并为研究生和本科生提供光声成像领域独特的多学科培训机会。

This project seeks to develop a novel photoacoustic (PA) microscopy system that would enable the mapping of deeply buried subsurface defects in optically opaque materials. Imaging of subsurface objects with sub-100 nm dimensions in opaque materials remains a major concern to integrated circuit reliability and performance. PA techniques combine the benefits of the large penetration depth of ultrasound with the lateral spatial resolution of an optical probe. However, the spatial resolution of PA techniques is limited by diffraction. To overcome these challenges, a novel approach is proposed for sub-wavelength PA technology by creating highly localized optical and ultrasound fields using: a) surface plasmonc nano-focusing for sub-100 nm confinement of the optical probe for high sensitivity detection of laser generated high frequency (0.5 - 10 GHz) ultrasound, and b) time reversal acoustics for spatial focusing of the scattered ultrasound field from nanoscale sub-surface objects. This PA system would provide an unprecedented spatial resolution and penetration depth for imaging sub-surface defects in microelectronic devices. The educational and out-reach programs proposed are deigned to excite high school level students to pursue careers in STEM and provide unique multidisciplinary training opportunities for graduate and undergraduate students in the area of photoacoustic imaging.