Tip-based femtosecond multiphoton spectroscopy with radiative heating

One of grand challenges in nanoscience and nanotechnology is to achieve fundamental under- standing of the dynamic evolution of materials in actual operating environment, non-equilibrium conditions, or undergoing chemical reactions at the nanoscale. This requires forefront advances in imaging and analysis techniques that combine nanometer-scale spatial resolution, optical excitation and spectroscopic detection for direct in-situ observation of the fundamental processes. The proposed innovation is in-situ nanoscale imaging method by integrating tip-based near-field scanning optical microscopy with femtosecond multiphoton spectroscopy, and by expanding its operational temperature beyond conventional range. First, the laser-heated stage enables high temperature operation up to 1000K since radiative heating can be precisely controlled and con- fined to a small volume at a short period of time. Second, design concepts and fabrication methods of near-field optical probe that is compatible with such extreme temperature are proposed, which is based on transparent, heat-resistant, and durable materials. Third, in-situ probe cleaning is applied to prolong the lifetime of optical probe and enhance the usability and reliability in harsh operating conditions.