All-Optical Multi-dimensional Imaging of Energy-Materials Beyond the Diffraction Limit

Efficient, environmentally-friendly, harvesting, storage, transport and conversion of energy are some of the foremost challenges now facing mankind. An important facet of this challenge is the development of new materials with improved electronic and photonic properties. Nano-scale metrology will be important in developing these materials, and optical methods have many advantages over electrons or proximal probes. To surpass the diffraction limit, near-field methods can be used. Alternatively, the concept of imaging in a multi-dimensional space is employed, where, in addition to spatial dimensions, the added dimensions of energy and time allow to distinguish objects which are closely spaced, and in effect increase the achievable resolution of optical microscopy towards the molecular level. We have employed these methods towards the study of materials relevant to renewable energy processes. Specifically, we image the position and orientation of single carbohydrate binding modules and visualize their interaction with cellulose with similar to 10nm resolution, an important step in identifying the molecular underpinnings of bio-processing and the development of low-cost alternative fuels, and describe our current work implementing these concepts towards characterizing the ultrafast carrier dynamics (similar to 100fs) in a new class of nano-structured solar cells, predicted to have theoretical efficiencies exceeding 60%, using femtosecond laser spectroscopy.