Optical Spectroscopy and Laser Desorption on a Nanometer Scale

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• 作者：Dieter Zeisel ; Bertrand Dutoit ; Volker Deckert ; Thomas Roth ; and Renato Zenobi
• 刊名：Analytical Chemistry
• 出版年：1997
• 出版时间：February 15, 1997
• 年：1997
• 卷：69
• 期：4
• 页码：749 - 754
• 全文大小：281K
• 年卷期：v.69,no.4(February 15, 1997)
• ISSN：1520-6882

文摘

Optical fiber tips for scanning near-field optical microscopy (SNOM or NSOM) produced by etching with theprotection layer method and subsequent metalizationshow an optical transmission of up to 0.5%. Thisthroughput is 2-4 orders of magnitude higher than that ofconventional pulled fiber tips. The high lighttransmissionpermits SNOM-based surface analytical and spectroscopicapplications with high spatial resolution (<100 nm) anda high chemical information content. Fluorescenceimaging of dye-labeled polystyrene spheres is demonstrated.Fast and irreversible photobleaching is shown to takeplace in the near field with enhanced efficiency.Surface-enhanced Raman spectra of cresol fast violet andp-aminobenzoic acid on a silver substrate are obtained inthe optical near field with a signal-to-noise ratio of>10.Rapid heating of chemically etched probes with pulsedlaser radiation can be used for thermal desorption ofmolecules from organic crystals and for modification ofpolymer surfaces. A lateral resolution of as little as75nm fwhm is achieved in the latter experiments.