Zheng Desheng, Lu Liyang, Kelly Kevin F, Baldelli Steven
Department of Chemistry, University of Houston , Houston, Texas 77204-5003, United States.
Department of Electrical and Computer Engineering, Rice University , Houston, Texas 77005, United States.
J Phys Chem B. 2018 Jan 18;122(2):464-471. doi: 10.1021/acs.jpcb.7b03339. Epub 2017 Aug 10.
Sum frequency generation microscopy is a label-free optical imaging technique with intrinsic molecular vibrational contrast for surface studies. Recent developments of compressive sensing broad-band hyperspectral SFG microscopy have demonstrated the potential application for imaging monolayer at metal surfaces with micrometer spatial resolution. Here is presented the capability of chemical imaging of spatially patterned monolayers of 1-octadecanethiol (ODT) and 16-methoxy-1-hexadecanethiol (MeOHT) molecules assembled on a copper surface. The spatial distributions of the monolayer with vibrational-spectral contrast are well-demonstrated at different frequency regions through reconstruction of the hypercube using a 3-dimensional total variation regularization algorithm (3DTV). Spatial-chemical distributions of each component are also reconstructed directly from the compressive measurements by endmember unmixing (CEU) scheme. Compared to 3DTV algorithm, the reconstruction from CEU shows spatial distribution of each component on the surfaces, and demonstrates the ability to characterize the domains of mixed-molecules on surfaces.
和频产生显微镜是一种用于表面研究的无标记光学成像技术，具有固有的分子振动对比度。压缩传感宽带高光谱和频产生显微镜的最新进展已证明其在以微米空间分辨率对金属表面的单层进行成像方面的潜在应用。本文展示了对组装在铜表面的1-十八烷硫醇（ODT）和16-甲氧基-1-十六烷硫醇（MeOHT）分子的空间图案化单层进行化学成像的能力。通过使用三维总变差正则化算法（3DTV）重建超立方体，在不同频率区域很好地展示了具有振动光谱对比度的单层的空间分布。每个组分的空间化学分布也通过端元解混（CEU）方案直接从压缩测量中重建。与3DTV算法相比，CEU的重建显示了表面上每个组分的空间分布，并展示了表征表面混合分子域的能力。
