EAGER: Enabling Quantum Leap: Temperature dependence of optical nonlinearities of monolayer transition-metal dichalcogenides

Stanford University, Stanford CA

Investigators

Abstract

This project contributes to efforts to develop a new class of optical quantum computing devices that are constructed using solid-state thin film materials and can operate at room temperature. Such new devices have the potential to revolutionize information technology, with applications ranging from cryptographic code-breaking to ultra-secure communication over networks. One of the most exciting features of the solid-state thin film materials investigated in this project is their potential to enable quantum information processing devices that require neither cryogenic nor high-vacuum environments, which add substantial bulk and complexity to prior approaches. This project specifically addresses a set of open questions regarding the room-temperature optical properties of monolayer thin films of the material molybdenum diselenide, the answers to which are crucial for predicting the best achievable performance of practical computing systems. Although bulk crystals of molybdenum diselenide have long been studied, the recent development of methods to prepare and characterize monolayer specimens - just a few atoms thick - have sparked new interest in this material because the properties of these thin films are markedly different from those of bulk samples. Above and beyond its implications for the development of practical quantum information technology, this research contributes to the interdisciplinary training of Ph.D. students and to the development of state-of-the-art educational materials for classroom teaching in emerging areas of quantum engineering. This project focuses on experimental and theoretical studies of the nonlinear optical responses and background optical absorption of monolayer transition-metal dichalcogenides over the temperature range from 4K to 300K. The project leverages recent advances in the use of laser annealing to prepare high quality large-area homogeneous samples of molybdenum diselenide, as well as recent theoretical calculations of Kerr-type nonlinearities associated with transitions among bound exciton states. The project aims to extend prior measurements and calculations to assess decoherence associated with exciton-phonon and exciton-exciton interactions at finite temperatures, and to arrive at quantum optical input-output models of transition metal dichalcogenide-based quantum photonic devices at room temperature with experimentally validated parameters. The project also aims specifically to assess the feasibility of constructing nonlinear photonic resonators based on stacks of multiple transition metal dichalcogenide monolayers, and to predict the best possible performance of such devices for quantum photonic information processing. Broader impacts of the project include interdisciplinary training of graduate students and the development of interdisciplinary material for graduate-level teaching at the intersection of quantum optics and quantum materials. 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.