Sub-diffraction illumination source for Saturated Transient Absorption Microscopy

Many emerging technologies in solar energy, electronics, and biophysics require a deep understanding of the behavior of materials on the nanoscale. Recent advances in high resolution chemical imaging show great promise for improving the resolution of widely applicable chemical imaging techniques. We propose to develop a commercial, tunable, low-noise, ultrashort pulse laser source with sub-diffraction illumination capabilities that will help make super resolution chemical imaging available to a broad range of scientists. Our approach is to build an optical parametric amplifier (OPA) based on our commercial fiber laser platform. This OPA will be added as additional layer on the existing fiber laser, keeping the footprint small. Two complimentary approaches to resolution enhancement will be investigated, and the higher-performing method integrated into the source, allowing us to end the program with a design for a fully packaged, turn-key, specifically-tailored tunable ultrafast source for subdiffraction illumination ready to be sold to academic markets and beyond. In Phase I, we constructed a laser source and, with our collaborators, demonstrated super resolution imaging. Through these imaging demos, we identified laser noise and repetition rate as limiting factors in imaging speed and quality. In Phase II, we will address these issues by increasing the repetition rate by and order of magnitude, and substantially decreasing laser noise. We will also demonstrate a novel, alternate approach to super resolution imaging, that, if successful, will substantially simplify the architecture, further lowering cost and complexity. Such a compact, robust, easy to use source for tunable, high-resolution chemical imaging could displace some users from large, complicated, and costly bulk laser solutions. Many researchers could benefit from such a system, improving image quality and enabling rapid development of next generation nanotechnology in fields as diverse as energy, electronics, and pharmacology.