Beyond the optical limit by tip enhanced nanospectroscopy in ambient

Authors

Norihiko Hayazawa ⋅ JP Surface and Interface Science Laboratory and Innovative Photon Manipulation Research Team, RIKEN and School of Materials and Chemical Technology, Tokyo Institute of Technology

Abstract

Despite the Ångstrom spatial resolution achieved by electron microscopes and scanning probe microscopes, optically "seeing" nanoscale objects in the ambient is a limitless demand of human because of its high chemical sensitivity, which has led to the development of near-field optics, and recently, super-resolution optics. On one hand, scientists are still trying to improve the spatial resolution of each technique. On the other hand, it is equally important to develop spectroscopic method to distinguish different chemical species. While optical spectroscopy method provides various chemical information, the spatial resolution has been very poor due to diffraction limit of light as compared to electron microscopy, SEM and TEM or scanning probe microscopy, AFM, and STM. However, since its inception in the year 2000, tip-enhanced Raman spectroscopy (TERS) has been recognized as one of the promising spectroscopic techniques in nanoscale due to the plasmonic properties of tip-enhancement, which work for both photon confinement and enhancement. From the scientific point of view, lots of efforts have been paid for the improvement of spatial resolution and sensitivity. One of the promising approaches is utilizing nonlinear response of material such as the narrowband coherent anti-Stokes Raman scattering (CARS) and broadband CARS. The other approach recently on trend is the hot spot engineering of gap-mode plasmon based on scanning tunnelling microscopy (STM) based TERS, which achieved up to ~1 nm spatial resolution both in UHV and in ambient.
In this contribution, we report an extremely high spatial resolution down to 1.7 nm in tip-enhanced Raman spectroscopy, which is currently the highest spatial resolution that has been achieved in Raman spectroscopy in ambient. While developing the optical microscope with high spatial resolution, a natural question subsequently arises as to how short excitation is possible with such an extremely high spatial resolution since one of the virtues of optical excitations is its high temporal resolution that is not attainable by any other techniques. We demonstrate a generation of extreme spatio-temporally confined nano-light source exhibiting 10 fs in time. The mechanism is based on degenerated four-wave mixing (FWM) at a sharp metallic tip. We will discuss the potential applications of tip-enhanced Raman and nonlinear Raman spectroscopy and microscopy based on our extreme spatial and temporal resolution.

About the Speaker

Norihiko Hayazawa, Surface and Interface Science Laboratory and Innovative Photon Manipulation Research Team, RIKEN and School of Materials and Chemical Technology, Tokyo Institute of Technology

Norihiko Hayazawa obtained his PhD degree from the Department of Applied Physics of Osaka University in 2001. From 2001 to 2004 he was a postdoctoral researcher supported by the Japan Society for the Promotion of Science (JSPS) and the Japan Science and Technology Agency (JST). He worked at RIKEN as a Research Scientist from 2004 up to 2008, when he became a Senior Research Scientist. Since 2012, he has also been a Visiting Associate Professor at the Tokyo Institute of Technology. He has been recognized by the Optical Society of Japan (Near-field Optics Award, 2000; Optics Paper Award, 2013), the Japanese Ministry of Education, Culture, Sports, Science and Technology (The Young Scientists' Prize, 2012), and the Spectroscopical Society of Japan (Award for Young Scientists, 2012). In 2013 he has also received a RIKEN Incentive Research Award and, more recently in 2014, the 17^th Marubun Research Promotion Foundation Research Incentive Award. His current research interests are in the fields of near-optics, nonlinear optics, vibrational spectroscopy, scanning probe miscroscopy, and surface science.

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Issue

2016: Proceedings of the 34th Samahang Pisika ng Pilipinas Physics Conference

Article ID

SPP-2016-1A-01

Section

Invited Presentations

Published

2016-08-18

How to Cite

[1]

N Hayazawa, Beyond the optical limit by tip enhanced nanospectroscopy in ambient, Proceedings of the Samahang Pisika ng Pilipinas 34, SPP-2016-1A-01 (2016). URL: https://proceedings.spp-online.org/article/view/SPP-2016-1A-01.