Distinguishing Single-Metal Nanoparticles with Subdiffraction Spatial Resolution Using Variable-Polarization Fourier Transform Nonlinear Optical Microscopy  

作　　者：Megan A.Steves Kenneth L.Knappenberger,Jr 

机构地区：[1]Department of Chemistry,The Pennsylvania State University,University Park,Pennsylvania 16802,United States [2]California Institute for Quantitative Biosciences,University of California,Berkeley,Berkeley,California 94720,United States

出　　处：《Chemical & Biomedical Imaging》2023年第1期91-98,共8页化学与生物医学影像（英文）

摘　　要：The development and use of interferometric variablepolarization Fourier transform nonlinear optical(vpFT-NLO)imaging to distinguish colloidal nanoparticles colocated within the optical diffraction limit is described.Using a collinear train of phase-stabilized pulse pairs with orthogonal electric ffeld vectors,the polarization of nonlinear excitation ffelds are controllably modulated between linear,circular,and various elliptical states.Polarization modulation is achieved by precise control over the time delay separating the orthogonal pulse pairs to within hundreds of attoseconds.The resultant emission from gold nanorods is imaged to a 2D array detector and correlated to the excitation ffeld polarization and plasmon resonance frequency by Fourier transformation.Gold nanorods with length-to-diameter aspect ratios of 2 support a longitudinal surface plasmon resonance at approximately 800 nm,which is resonant with the excitation fundamental carrier wavelength.Differences in the intrinsic linear and circular dichroism resulting from variation in their relative alignment with respect to the laboratory frame enable optical differentiation of nanorods separated within 50 nm,which is an approximate 5-fold improvement over the diffraction limit of the microscope.The experimental results are supported by analytical simulations.In addition to subdiffraction spatial resolution,the vpFT-NLO method intrinsically provides the polarization-and frequency-dependent resonance response of the nanoparticles�providing spectroscopic information content along with super-resolution imaging capabilities.

关 键 词：nonlinear optics POLARIZATION circular dichroism imaging Fourier transform spectroscopy PLASMONS super-resolution microscopy 

分 类 号：TH742[机械工程—光学工程] TB383[机械工程—仪器科学与技术]