Ultrafast infrared chemical nano-scope: Femtosecond spatio-temporal nanoimaging and spectroscopy

Anasys Instruments in collaboration with Markus Raschke (University of Colorado, Boulder) propose to jointly develop a new ultrafast infrared and optical scanning probe nano-scope, based on scattering scanning near-field optical microscopy (s-SNOM), that provides both spatio-spectral and spatio-temporal nano-imaging. Nanoscale heterogeneity defines properties and performance in many functional materials systems, involving complex charge, ion, and interfacial interactions and energy tran sfer. It has long been a problem of both fundamental and practical interest to probe these interactions on their natural time and length scales. The combination of s-SNOM and ultra-fast laser spectroscopy techniques has opened the window to measurements on nanometer length scales and fs time scale, but successful implementations of this combination exist only in very few specialized laboratories around the world. However, key limitations in commercially available ultrafast IR lasers, tip material design, and signal detection prevent a broader proliferation of ultrafast IR nano-imaging and nano-spectroscopy. This SBIR project proposes to overcome the current barriers to develop a tabletop instrument will that make possible ultrafast IR nano-imaging and nano-spectroscopy with unprecedented few nanometer spatial resolution and <100 fs temporal resolution for a diverse range of chemical and materials systems. The proposed instrument will be capable of providing: (1) Routine ultrafast IR s-SNOM imaging and spectroscopy on organic and inorganic materials with novel scanning probe atomic force control; (2) Combined spatiotemporal vibrational nano-imaging and spectroscopy with advanced atomic-force nano-mechanical proves for multimodal and correlative imaging; (3) Non-invasive and non-perturbative ultrafast near-field probe for insight into structure, coupling, and dynamics of molecular systems in their local functional environment. During Phase I we will use coherent light sources readily available in the Raschke group, combined with a commercial nanoIR2-s AFM system developed by Anasys to test novel methods to performing ultrafast s-SNOM. We will find the parameters necessary to optimally combine ultrafast pulsed laser sources with nano-scale imaging and spectroscopy, demonstrating the feasibility of advanced high-speed data acquisition algorithms and balanced signal detection to completely eliminate laser noise and drift. During Phase II, we will partner with a laser vendor to develop and commercialize a complete and robust ultrafast IR s-SNOM platform that will provide turnkey, routine spatiotemporal nano-imaging and nano-spectroscopy with femtosecond time resolution and nanometer spatial resolution. It is expected that a successful completion of our program will further broaden the interest and application of s-SNOM in the greater scientific community, rather than being confined to the laboratory of advanced experimental research groups who specialize in near-field methods. The ability to probe coherent ultrafast dynamics opens a new exploratory regime in spatiotemporal imaging science. Ultrafast pump-probe spectroscopy, for example provides access to the coupled degrees of freedom including spin, charge, and lattice dynamics that underlie the complex properties of correlated and quantum materials. This project will help serve the great interest in driving and probing systems away from equilibrium, monitoring relaxation in both time and space, coupled laterally across heterogeneities in a wide range of materials systems. Critical application areas will include molecular electronics, quantum dots, functional polymers, light harvesting systems in biology, charge dynamics in OLEDs and OPVs, hybrid perovskite solar cells, LiFePo battery electrodes and the solid-electrolyte interface (SEI) layer, heterogeneous nano-interfaces throughout the life sciences including microbiology and geochemistry, correlated electron and 2D quantum materials, and heterostructures for light-harvesting and energy applications in general.