Technologies that rely on and exploit the quantum properties of light and matter are touted as the next phase of the modern industrial revolution. Light has become the preferred medium for information transfer in quantum technologies due to its high speed and exceptional noise properties, with single photons acting as the most basic building blocks. However, the realization of robust, device-compatible, room-temperature single photon sources that can be activated and controlled on demand has been a major hurdle. Although there have been different material systems that have shown single photon emission, they operate at low temperature or at incompatible wavelengths, and are often hard to integrate with conventional photonic materials or CMOS technology. To address this challenge, this project aims to develop single photon emitters based on cavity-coupled van der Waals (vdW) materials. Specifically, the program will focus on hexagonal boron nitride, a wide bandgap semiconductor that can host optically active point defects with emission in the visible and near infra-red. Combining defect engineering and "pick-and-place" techniques, the project will develop a range of light-confining hybrid structures designed to enhance light collection and light emission from single photon emitters as well as increase the strength of light-matter interaction. The overarching goal is to develop the key building blocks for realizing quantum photonic devices based on vdW materials.
The development of quantum photonic technologies that can operate at elevated temperatures, are CMOS compatible, and can be integrated with conventional photonics is highly desirable. This project addresses precisely this need through the use of monolayer or few-layer vdW materials integrated with silicon nitride photonic platforms where we exploit the unique strengths of the two material systems. vdW materials are a highly attractive platform for active components in quantum photonics due their large light-mater interaction strength, compatibility with a variety of substrates, and pick-and-place fabrication techniques. In particular, hexagonal boron nitride has a wide bandgap (6 eV), which allows for a broadly accessible spectral range and mid gap defect states. Furthermore, owing to the few-layer vdW structure, these systems show extreme susceptibility to strain and the dielectric environment, which will be exploited to control defect activation and integration with nanophotonic structures such as microresonators and waveguides. Silicon nitride, already recognized as an excellent material for passive photonic devices due to its low loss and mature fabrication protocols will form the platform for realizing the quantum photonic chips. Specific program goals include: (i) Deterministic engineering of defect states in hBN for single photon emission, and (ii) Integration of emitters into micro-resonators and hybrid cavity systems for enhancing spontaneous emission and achieving the strong coupling regime. The program will help train students from diverse backgrounds in the emerging interdisciplinary field of quantum optoelectronics. A highlight among the planned outreach activities is a hands-on quantum technologies workshop for undergraduate students at City College.
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.
