CAREER: Rapid Manufacture of Three-Dimensional Nanostructures for Nano-enabled Devices Using Projection Two-Photon Lithography

This Faculty Early Career Development (CAREER) grant focuses on fundamentally transforming the three-dimensional printing of complex nanostructures using two-photon lithography from a slow and poorly scalable guesswork-based approach to a rapid and resource-efficient knowledge-based approach. The two-photon lithography process, which uses lasers to direct print three-dimensional structures in photopolymers, fills an important technology gap between microfabrication that is limited to planar geometries and typical additive manufacturing that cannot print structures with nanoscale features and precision.

The two-photon lithography process is therefore critical for the fabrication of three-dimensional nano-enabled devices with applications in emerging fields such as quantum information processing, electric transportation and biomedicine, which are important to national prosperity and welfare. However, it has remained a niche process due to the low printing rates and limited process knowledge.

Industrial-scale adoption is particularly challenging due to the slow and labor-intensive iterative ad-hoc experimentation involved in predicting the process inputs for a desired print geometry. This project elucidates the fundamental relationships between process parameters and product performance for a projection-based high-speed implementation of two-photon lithography.

The research is complemented by an educational and outreach program centered around project-based experiential learning for training of manufacturing workforce, K-12 students and teachers, and undergraduate and graduate students, with a focus on reducing the barriers to diversity, equity and skills acquisition in advanced manufacturing.

The specific goal of the research is to generate the processing science for high-throughput three-dimensional printing of nanostructures using projection two-photon lithography. This project advances three core research areas: (1) the coupling between light-matter interactions at high intensities (approaching terawatts per square cm), (2) polymerization at short time and small length scales (i.e., on millisecond and submicron scales), and (3) effect of polymerization on the physical properties of the printed nanoscale features.

The specific research objectives are: (i) generation of physics-based relationships to predict printability and print geometry, (ii) elucidating the mechanisms that determine the rate limits, and (iii) developing error compensation techniques to minimize defects during printing of large structures with nano-scale precision. The research seeks to answer three fundamental questions about the process. (1) Can broadly generalizable predictive relationships be generated? (2) What are the theoretical and practical printing rate limits? (3) Is error compensation feasible?

These are answered through a combination of physics-based computational modeling of the underlying physical phenomena, validation of models against previously unmeasurable empirical data, and in-situ process monitoring and control. This project advances additive nanomanufacturing of nano-enabled devices using scalable processing techniques.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.