CAREER: Towards Super-Resolution Label-Free Mid-Infrared Photothermal Imaging

在纳米科学、化学过程、病理学和污染监测中识别低浓度样品仍然是现有的材料分析挑战。使用红外显微镜，可以以非接触式方式直接确定材料的固有特性，而不需要使用外部标签、污渍或纳米颗粒进行广泛和侵入性的样品制备。在拟议的新型成像平台中，同时进行化学、光学和热材料表征将提供对分子样品组成的独特一瞥。这种光热显微镜可以采集高空间分辨率的图像，而不是受到长光学红外波长设置的较低分辨率的限制。这项技术将被应用于确定侵袭性脑癌的肿瘤边缘，并表征经历尺寸变化的智能材料，以推进基本材料特性研究、诊断和潜在的药物治疗。作为研究的桥梁，显微镜、光纤激光、生物医学分析和化学光谱分析，它为培养本科生和研究生研究人员提供了一个独特的跨学科环境，以实现广泛的职业选择。国际和平协会的目标是通过从社会各界和团体招募人才，并提供有针对性的培训和指导，建立一个多元化和包容性的社区。为了扩大光学领域的参与并解决STEM中的性别差距，国际和平协会将在当地(波士顿妇女参与光子网络系列)和国际范围(在会议上的陈述反馈计划)上发起外展活动和专业发展活动。这些举措将支持PI为多样化的创新下一代工程师和科学家提供支持的愿景。技术PI的长期愿景是建立一个集成的研究和教育计划，通过将创新的光学方法与定制设计的光纤激光技术相结合，探索多维、非接触式超分辨率成像，以增强材料分析和跨学科传感应用。总体目标是研究光热成像中吸收、热扩散、非平衡诱导相变和热模糊动力学之间的相互作用。然后，这些新颖的光热概念将被集成到一个无标签和非破坏性的超分辨率成像设备平台中，该平台将提供有关生化光谱特征和热物理特性的丰富细节。这将解决现有的科学挑战，即识别可能经常在重叠光谱带中被遮盖的弱吸收特征。具有中红外泵浦和较短波长探测光束的光热成像能力将通过研究新的非线性材料和解调方案来实现更高的空间分辨率。这些概念的结合有望在微米和纳米尺度上对非平衡光热现象和热扩散特性提供新的见解，同时提供超出衍射限制的探测光束光斑大小的空间分辨率，具有前所未有的化学专一性。这项研究的影响和多功能性将通过监测脑癌组织和智能材料中的材料特性及其生化特征来展示。该奖项反映了NSF的法定使命，并已通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Identifying low concentration specimens in nanoscience, chemical processes, pathology, and contamination monitoring remains an existing material analysis challenge. With an infrared microscope intrinsic material properties can be directly determined in a contactless fashion without the need for extensive and intrusive sample preparation with external tags, stains or nano-particles. In the proposed novel imaging platform, simultaneous chemical, optical and thermal material characterization will offer unique glimpses into the molecular sample composition. Instead of being limited by poorer resolution set by the long optical infrared wavelengths, high spatial resolution images can be collected in such a photo-thermal microscope. The technique will be applied to determine tumor margins in aggressive brain cancers and to characterize smart materials that undergo size changes to advance fundamental material property studies, diagnosis and potential drug therapies.As the research bridges microscopy, fiber lasers, biomedical analysis and chemical spectroscopy, it offers a unique interdisciplinary environment for the training of undergraduate and graduate researchers for a wide range of career choices. The PI aims to build up a diverse and inclusive community by recruiting talent from all sectors and groups of society and by offering targeted training and mentorship. To broaden participation for optics and address the gender gap in STEM, the PI will launch outreach activities as well as professional development activities on a local (Boston Women in Photonics Networking Series) and international scale (presentation feedback program at conferences). These initiatives will support the PI's vision of empowering a diverse group of innovative next generation engineers and scientists.TechnicalThe PI's long-term vision is to build an integrated research and education program that explores multi-dimensional, contactless super-resolution imaging by merging innovative optical approaches with custom-designed fiber laser technology for enhanced material analysis and interdisciplinary sensing applications. The overall aim is to study the interplay between absorption, thermal diffusion, non-equilibrium induced phase transitions and thermal blurring dynamics in photo-thermal imaging. These novel photo-thermal concepts will then be integrated into a label-free and non-destructive super-resolution imaging device platform that will deliver rich details on both biochemical spectral signatures and thermo-physical characteristics. This will address existing scientific challenges of identifying weakly absorbing features that can frequently be overshadowed in overlapping spectral bands. Photo-thermal imaging capabilities, with a mid-infrared pump and a shorter wavelength probe beam, will be expanded by studying novel nonlinear material and demodulation schemes for higher spatial resolution. The combination of these concepts promises new insights into non-equilibrium photo-thermal phenomena and thermal diffusive properties at the micro- and nano-scale while offering spatial resolutions beyond the diffraction limited spot size of the probe beam with unprecedented chemical specificity. The impact and versatility of the research will be demonstrated by monitoring material properties and their biochemical signatures in brain cancer tissue and smart materials.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.