STTR Phase I: Surface- and Structural Engineering of Colloidal Quantum Dots Towards Efficient and

This Small Business Technology Transfer Research Phase I project will develop high-efficiency two-photon lasers based on microbeads doped with colloidal quantum dots (QDs) for applications in coherent-optical coding. Current two-photon lasing materials are generally organic dyes which exhibit fast photobleaching decay and low efficiencies. We propose to develop colloidal QD-based two-photon lasing materials that are efficient, photochemically stable, and able to enable effective pumping deep within biological samples. To develop a viable two-photon lasing product, featuring improved lasing stability, prolonged operation lifetime, enhanced upconversion efficiency, and reduced pumping threshold, the following objectives are proposed in the Phase I project: 1) Design engineered nanostructures that can significantly increase the two-photon absorption efficiency; 2) Study lasing efficiency and stability of the designed nanostructures; 3) Explore the applications of two-photon lasing in coherent optical coding. We expect to obtain stable, high-efficiency, and low-threshold QD lasing materials and QD-doped microbead lasers exhibiting multiple lasing wavelengths which could play key roles in biological barcode sensing and many other applications. In Phase II, we will collaborate with strategic partners to develop coherent optical barcoding based on the Phase I results, with the goal of high-accuracy and high-throughput analysis of biological molecules. The broader impact/commercial potential of this project is to produce stable and high-efficiency two-photon lasing materials and systems which can be used in medical and biological barcodes and on-chip nanolasers to advance the technologies of bio-medical sensing, clinical diagnostics, optical data storage, and telecommunications. The successful completion of this project will offer inexpensive, tunable-wavelength, and durable lasing systems for use in the $3.5 billion diode laser market. In particular, the proposed QD-based two-photon lasing materials can be employed in biological optical barcoding with key applications for accurate, rapid and multiplexed diagnostics of diseases, as well as drug screening, with corresponding health care and environmental benefits. The proposed work will provide focused research and training experience for undergraduate and graduate students by involving them in laboratory work, and will help them to connect fundamental nanoscience knowledge with the real-world applications of nanotechnology.