Combination of a fs-laser with a STM
The aim of this project is the reassembling and implementing of a low-temperature STM with a fs-laser system. Both methods were used successfully for decades. The combination of both techniques enables unique insights in the behavior of single atoms and molecules.
Schematic view of the combined STM and fs-laser system [Mehlhorn et al., Rev. Sci. Instrum. 78, 033905 (2007)].
The low-temperature STM is cooled by liquid helium to a temperature of 5 K, realizing a resolution of 1 pm in lateral and <1 pm in vertical direction. The fs-laser is coupled to the STM by an optical system, focussing the beam onto the sample surface. The laser pulses have a FWHM of 30 fs at a wavelength of 400 nm.
The system is therefore able to resolve adsorbed molecules on a surface atomically, while the laser gives a time-resolution in the fs-range.
The performance of the setup is currently tested with „simple“, known systems, as for example the diffusion of CO on Cu(111).