Invited Paper NS-WeA7
Near-Field Spatio-Temporal Control of Optical Fields for Spectroscopic Nano-imaging: Ultrafast Spectroscopy Reaching the Single Molecule Limit
Combining plasmonic and optical antenna concepts with ultrafast and shaped laser pulses allows for the precise control of an optical excitation on femtosecond time and nanometer length scales. I will present several new concepts extending tip-enhanced spectroscopy into the nonlinear and ultrafast regime for nano-scale imaging and spectroscopy of surface molecules and nano-solids. Examples include the adiabatic nano-focusing on a tip for background free tip-enhanced Raman nano-spectroscopy, and spatio-temporal superfocusing with optical control at the 10 nm-10 fs level. Furthermore, the combination of ultrafast mid-IR femtosecond pulses with scattering-scanning near-field optical microscopy (s-SNOM) allows for the control of the ultrafast free-induction decay of infrared molecular vibrations with an increase in sensitivity of IR surface spectroscopy by 109 compared to conventional IR micro-spectroscopy, reaching the single molecule limit.