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

Trustees Of Boston University, Boston

Investigators

Abstract

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. Technical The 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.