Atomic-scale Photochemistry

Introduction

Photochemistry entails natural and artificial reactions that are activated optically and is at the heart of fundamental processes such as photosynthesis, vision, polymerization, catalysis, or energy conversion. Innovative approaches to gain control over photochemical reactions that relied on macro- and mesoscale manipulations of light (e.g., chemistry in an optical cavity, plasmon-enhanced reactions, etc.) were reported recently. However, no strategy was proposed to address the photochemistry of a molecule with atomic-scale precision.

Project Aim

AETHER aims to provide a disruptive photochemical method whose fundamental concept is based on the manipulation of light with ultimate spatial accuracy. This approach relies on the confinement of a laser excitation – pulsed or continuous – into an extremely small volume at the apex of a scanning probe tip, eventually acting as a plasmonic picocavity. This confined electromagnetic field can then be moved on top of organic structures where it locally generates photo reactions.

Research Questions

AETHER aims at addressing questions in a wide range of fields related to physical chemistry:

1. Can one generate photochemical reactions in a sub-unit of a molecule while preserving the rest of it? Can one use this site-specific approach to synthesize new molecular species?
2. To what extent can we deepen our understanding of fundamental natural processes (e.g., energy transfer, photo-isomerization) at play, for example, in photosynthesis and vision?
3. Can we combine this atomic-scale optical approach with time-resolved techniques to follow photochemical reactions in real time and real space?

Methodology

Answering these questions requires probing, manipulating, and exciting molecules with atomic and sub-picosecond precision. To this end, a scanning probe microscope associated with laser excitation sources will be developed to provide simultaneous spatial, spectral, and temporal control over different types of photochemical reactions.