Andreas Tittl

Publications (3)26.4 Total impact

• Article: Plasmonic Smart Dust for Probing Local Chemical Reactions.

  Andreas Tittl, Xinghui Yin, Harald Giessen, Xiang-Dong Tian, Zhong-Qun Tian, Christian Kremers, Dmitry N Chigrin, Na Liu
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  ABSTRACT: Locally probing chemical reactions or catalytic processes on surfaces under realistic reaction conditions has remained one of the main challenges in materials science and heterogeneous catalysis. Where conventional surface interrogation techniques usually require high-vacuum conditions or ensemble average measurements, plasmonic nanoparticles excel in extreme light focusing and can produce highly confined electromagnetic fields in subwavelength volumes without the need for complex near-field microscopes. Here, we demonstrate an all-optical probing technique based on plasmonic smart dust for monitoring local chemical reactions in real time. The silica shell-isolated gold nanoparticles that form the smart dust can work as strong light concentrators and optically report subtle environmental changes at their pinning sites on the probed surface during reaction processes. As a model system, we investigate the hydrogen dissociation and subsequent uptake trajectory in palladium with both "dust-on-film" and "film-on-dust" platforms. Using time-resolved single particle measurements, we demonstrate that our technique can in situ encode chemical reaction information as optical signals for a variety of surface morphologies. The presented technique offers a unique scheme for real-time, label-free, and high-resolution probing of local reaction kinetics in a plethora of important chemical reactions on surfaces, paving the way toward the development of inexpensive and high-output reaction sensors for real-world applications.
  Nano Letters 03/2013; · 13.20 Impact Factor
• Article: Palladium-based plasmonic perfect absorber in the visible wavelength range and its application to hydrogen sensing.

  Andreas Tittl, Patrick Mai, Richard Taubert, Daniel Dregely, Na Liu, Harald Giessen
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  ABSTRACT: We report on the experimental realization of a palladium-based plasmonic perfect absorber at visible wavelengths and its application to hydrogen sensing. Our design exhibits a reflectance <0.5% and zero transmittance at 650 nm and the operation wavelength of the absorber can be tuned by varying its structural parameters. Exposure to hydrogen gas causes a rapid and reversible increase in reflectance on a time scale of seconds. This pronounced response introduces a novel optical hydrogen detection scheme with very high values of the relative intensity response.
  Nano Letters 09/2011; 11(10):4366-9. · 13.20 Impact Factor
• Article: Spectral shifts in optical nanoantenna-enhanced hydrogen sensors

  Andreas Tittl, Christian Kremers, Jens Dorfmüller, Dmitry N Chigrin, Harald Giessen
  Optical Materials Express. 2(2):111.