SBIR Phase I: Quantitative space-time control for high contrast multiphoton microscopy

This Small Business Innovation Research Program (SBIR) Phase I project will develop improvements to multiphoton microscopy, especially two-photon excitation fluorescence (TPEF). This technology has radically changed the manner in which quantitative biological studies are performed. It is now the tool of choice in dynamic, high-resolution (sub-micrometer) studies because scattering is mitigated, penetration depths can reach 1 mm, and impact of the excitation wavelength is minimized (near-infrared wavelengths are significantly less harmful to living systems.) However, challenges that limit application of TPEF imaging are setup time, image optimization and consistency. By rapidly measuring pulse characteristics, in situ, within the imaged sample itself, using this information to perfectly adjust pulse characteristics at the imaged point, in situ, within the sample itself, sample setup times can be improved and images can be made to be brighter, higher contrast and have better consistency. This holds for both commercial imaging systems using pulse width ranges from 70-100 fs, as well as home-built systems using pulse widths of 50 fs or less. This project will develop a novel, drop-in device, useable on any multiphoton microscopy system that will enable completely automated sample setup for the biologist to produce higher quality TPEF images faster, with better consistency. The broader impact/commercial potential of this project is the development of instrumentation and control systems to facilitate the improved utility of ultrafast lasers for new and important applications by allowing the production of high-contrast femtosecond pulses. These pulses are transform-limited in space and time, which not only impacts imaging, but all commercial applications of femtosecond lasers. For example, plasma-mediated ablation utilizes amplified femtosecond pulses and is a powerful process that is incorporated in a broad range of industries includes microfluidic platforms, and cataract surgeries, such as femtosecond laser assisted cataract surgery as well as Laser-Assisted in Situ Keratomileusis (LASIK) procedures. Current technologies only facilitate pulse optimization prior to the focus and interaction region. In fact, present femtosecond laser eye-surgery is based on twenty-year old technology. As industries begin to re-tool to take advantage of the benefits of improved femtosecond lasers, new pulse enhancement tools, such as proposed here, will be imperative to their successful implementation.