Controlling strong electromagnetic fields on nanoparticles is important to trigger targeted molecular reactions on their surfaces. This control over strong fields is achieved via laser light. Laser-induced formation and breaking of molecular bonds on nanoparticle surfaces have been observed in the past. But nanoscopic optical control of surface reactions has not yet been achieved. Dr. Boris Bergues and Prof.
Matthias Kling at Ludwig-Maximilians-Universität (LMU) and the Max Planck Institute of Quantum Optics (MPQ) have closed this gap. The physicists determined the location of light-induced molecular reactions on the surface of isolated silicon dioxide nanoparticles using ultrashort laser pulses.
There is hustle and bustle on the surface of nanoparticles. Moleculesdissolve and change their location. All this drives changes matter and even gives rise to new materials. The events in the nano cosmos can be controlled with the help of electromagnetic fields. Scientists used strong and femtosecond-laser pulses to generate localized fields on the surfaces of isolated nanoparticles. A femtosecond is one-millionth of a billionth of a second.
Scientists developed a new technique by using reaction nanoscopy. They were able to image the reaction site and birthplace of molecular fragments on the surface of silica nanoparticles.
The nanoscopic spatial control was brought about by the scientists by superimposing the fields of two laser pulses with different colors. They had to set the time delay between the two pulses with attosecond accuracy. An attosecond is still a thousand times shorter than a femtosecond.
Molecular surface reactions on nanoparticles play a fundamental role in nanocatalysis. The new results pave the way for tracking photocatalytic reactions on nanoparticles not only with nanometer spatial resolution. This will provide detailed insights into the surface processes on the natural spatial and temporal scales of their dynamics.