Atomic Force Microscope Active Optical Probe for Single-Molecule Imaging and Time-Resolved Optical Spectroscopy

While science and technology fields greatly benefit from Atomic Force Microscopy (AFM) in surface characterization, time-resolved chemical imaging on the single-molecule level, e.g., Near-Field Scanning Optical Spectroscopy and Ultrafast Tip-Enhanced Spectroscopy, lags far behind — current scanning probe microscopy only obtains information about mechanical, but not chemical/optical properties. To address this technical challenge, a novel class of atomic force microscopy probes will be developed that will allow ultrafast time-resolved optical and chemical imaging at the nanoscale. As envisioned, these unique optical probes will perform the functions of conventional atomic force microscopy probes and, in addition, will simultaneously provide chemical information about molecular scale interactions, including energy flow, molecular dynamics, breakage/formation of chemical bonds, and conformational changes in nanoscale systems. This innovation will be accomplished by integrating an ultrafast pulsed laser source and a photodetector monolithically into an atomic force microscopy probe. The Small Business Innovation Research Phase I and Phase II projects were focused on the integration of an ultrafast micrometer size laser with an atomic force microscopy probe. Microscopy probe tips made from gallium arsenide (GaAs) instead of silicon were fabricated and tested. The GaAs-based laser was then fabricated, tested, and integrated into a GaAs AFM probe. The overall goal of the Phase IIA project is to continue development and validation of the innovative AFM active optical probe with its monolithically integrated mode-locked semiconductor laser and internal photodetector for nano-imaging and time-resolved spectroscopy. In Phase IIA, the probe will be prototyped utilizing several different methods to optimize its performance, a prototype will be built for field testing, and the probe’s technical and economic potential will be validated through performance tests and analysis. Commercial Applications and Other Benefits: Successful results of the Phase IIA project will make a significant commercial contribution to the field of atomic force microscopy, enabling the production and commercialization of novel hybrid scanning probe microscopes. These microscopes will combine conventional atomic force microscopy and ultrafast time- resolved spectroscopy for solving critical research challenges and improving the precision of analysis for the chemistry, medical and semiconductor industries. This technology also has the potential to drastically improve the technical performance of data storage components such as hard drives and optical memory devices.