SoftMeter · Multi-messenger soft-field spectroscopy of molecular electronics at interfaces

The real-time interrogation of molecular electronics at the interface between different media is key to understanding the fundamental mechanisms at the basis of processes such as catalysis, solar energy harvesting, and charge transport in optoelectronic devices. Such an investigation ultimately requires attosecond temporal resolution and picometer spatial accuracy, to capture in real-time the energy exchanges mediated by the electron wave function and the competing structural changes of the target. Experimental strong-field-laser physics has been demonstrated to provide outstanding spectroscopical methods for this purpose, such as high-harmonic generation spectroscopy, attosecond science, and laser-induced electron diffraction. However, it also presents intrinsic limitations such as high peak intensities, low efficiency, and poor tunability. These obstacles have so far hindered its application to the study of high-complexity systems, for example complex interfaces.SoftMeter aims at filling this gap. We are proposing a novel multi-messenger two-color spectroscopy, namely soft-field spectroscopy, that converts the concepts of strong-field physics into the moderate or weak field regime and overcomes its limitations, while still providing an unprecedented spatiotemporal resolution. The new protocol will be developed in the first phase of the project: It is based on an interferometric setup combining few-fs ultraviolet pulses with few-cycle IR pulses, and on the multi-messenger measurement of the laser-induced electron diffraction and the high-harmonic radiation of the target. In the second phase of the project, the novel soft-field scheme will be employed for the real-time interrogation of electronics at molecular interfaces.SoftMeter will pave the way for a new class of ultrafast laser spectroscopy experiments, with a large impact on several disciplines, ranging from photo-chemistry to biology, as well as from energetics to environmental science.