The development of advanced quantum networks used in computing and communications heavily relies on the ability to transmit information coherently within the electromagnetic spectrum. Researchers at the State University of Campinas (UNICAMP) in Brazil, in collaboration with colleagues at ETH Zurich in Switzerland and TU Delft in the Netherlands, have conducted a pioneering study focused on the use of nanometric optomechanical cavities to achieve this goal. With the aim of promoting interaction between high-frequency mechanical vibrations and infrared light, which are key components of the telecommunications industry, these nanoscale resonators demonstrate promising potential for the future of quantum technology. Published in the journal Nature Communications, the study sheds light on the significance of dissipative optomechanics in this field.
“Nanomechanical resonators act as bridges between superconducting circuits and optical fibers,” says Thiago Alegre, a professor at the Gleb Wataghin Institute of Physics (IFGW-UNICAMP) and last author of the article. Superconducting circuits, which are currently at the forefront of quantum computing technologies, can benefit from the seamless integration with optical fibers for long-distance information transmission. The existing optomechanical devices mainly rely on dispersive interaction, where only photons confined in the cavity are efficiently dispersed. However, the team’s research introduces dissipative optomechanics, where photons can be scattered directly from the waveguide to the resonator, allowing for tighter control of the optoacoustic interaction.
The study represents a breakthrough as it demonstrates the first dissipative optomechanical system that operates in a regime where the mechanical frequency exceeds the optical linewidth. Before this research, dissipative optomechanical interaction had only been demonstrated at low mechanical frequencies, limiting its potential applications such as quantum state transfer between the optical and mechanical domains. By raising the mechanical frequency by two orders of magnitude and achieving a tenfold increase in the optomechanical coupling rate, the researchers have opened up new prospects for the development of more effective devices in the future.
In collaboration with TU Delft, the research team fabricated the nanometric silicon beams that were crucial to the success of the study. These beams were suspended and free to vibrate, enabling the confinement of both infrared light and mechanical vibrations simultaneously. To facilitate the coupling of the optical fiber to the cavity, a waveguide was strategically positioned laterally, resulting in dissipative coupling. This key component was instrumental in achieving the results presented in the study. Additionally, the devices were designed using well-established technologies from the semiconductor industry, ensuring their practicality and scalability.
The study not only offers immediate applications for the construction of quantum networks but also lays the foundation for future fundamental research. As Alegre highlights, the ability to manipulate mechanical modes individually and mitigate optical non-linearities in optomechanical devices is an exciting prospect that this study brings forth. With the continuous advancement of nanometric optomechanical cavities, quantum networks can reach new levels of efficiency and performance, propelling the field of quantum computing and telecommunications forward.
The research conducted by the State University of Campinas, ETH Zurich, and TU Delft has showcased the immense potential of nanometric optomechanical cavities in the development of advanced quantum networks. The introduction of dissipative optomechanics and the achievement of higher mechanical frequencies have opened up groundbreaking opportunities for applications in quantum computing and long-distance information transmission. Through collaborative device fabrication and the utilization of well-established technologies, the team has successfully demonstrated the feasibility of these concepts. As we continue to delve deeper into the field of quantum technology, the study provides a solid foundation for further research and advancements in the realm of quantum networks.