Fast IR Imaging with Sub-wavelength Resolution Using a Transient Near-field Probe (Tipless Near-field Microscopy)

使用瞬态近场探头进行亚波长分辨率的快速红外成像（无针头近场显微镜）

• 批准号: 9819778
• 负责人: Todd Smith
• 金额: $ 40.24万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-05-01 至 2003-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9819778&HistoricalAwards=false
• 关键词: Fast; IR; Imaging; Sub; wavelength

9819778AbstractFast Infrared Imaging with Sub-Wavelength Resolution Using aTransient Near-Field Probe (Tipless Near-Field Microscopy)Sub-micron resolution "chemical" images of biological systems obtained through use of the intrinsic contrast parameters of molecules - their mid-infrared vibrational modes -are beginning to play an important role in research. Because the wavelengths in the region of interest are typically several microns, such high resolution images can only be obtained through the use of near-field techniques. To date, such techniques have relied upon some form of mechanical probe or tip made with sub-micron dimensions and mechanically scanned across the surface to be imaged while being maintained at a fixed sub-micron distance from the surface.We propose the development of a new approach to near-field microscopy in which imaging is based on a remote, optically generated transient near-field probe. Picosecond pulses of visible light incident on the surface of a semiconductor substrate will produce, through the phenomenon of photo-induced reflectivity, transient mirrors with dimensions determined by the size of the visible beam spot on the substrate. Infrared light scattered by such a sub-wavelength sized mirror will be collected afier propagating through the sample located on the substrate. Since the sample is located on the substrate, no near-field distance control will be required, and images will be available at the rate of conventional laser scanned microscopes. Further, since the near-field probe is generated remotely -using light - the sample to be imaged can be covered by, or encased in, a transparent liquid or solid.The microscope will combine a conventional inverted microscope with an infrared imaging system providing rapid sub-micron imaging simultaneously in the visible and infrared parts of the spectrum. In addition to conventional histologic sections, biological systems, including living cells, will be able to be imaged in liquid media.

摘要利用分子的中红外振动模式，即分子的内在对比参数，获得亚微米分辨率的生物系统“化学”图像，已开始在研究中发挥重要作用。由于感兴趣区域的波长通常为几微米，因此只有通过使用近场技术才能获得如此高分辨率的图像。迄今为止，这种技术依赖于某种形式的机械探针或亚微米尺寸的尖端，在与表面保持固定的亚微米距离的同时，对表面进行机械扫描以成像。我们提出了一种新的近场显微镜方法的发展，其中成像是基于一个远程的，光学产生的瞬态近场探针。皮秒可见光脉冲入射到半导体衬底表面，通过光致反射率现象，产生瞬态反射镜，其尺寸由衬底上可见光斑的大小决定。通过这种亚波长大小的反射镜散射的红外光在穿过位于衬底上的样品后将被收集。由于样品位于基板上，因此不需要近场距离控制，并且图像将以传统激光扫描显微镜的速度提供。此外，由于近场探测器是远程产生的——使用光——被成像的样品可以被透明液体或固体覆盖或包裹。该显微镜将传统的倒置显微镜与红外成像系统相结合，同时在光谱的可见和红外部分提供快速的亚微米成像。除了常规的组织学切片，生物系统，包括活细胞，将能够在液体介质中成像。