Harvard engineers create ultra-thin metasurface capable of replacing targets quantum optical installations.
Photons, the particles that make up light, are becoming increasingly promising for the rapid transmission of information. However, usually, to translate photons into the required quantum states, complex waveguides on large, bulky chips or installations of lenses, mirrors, and light guides. These components allow photons to be converted into a state of quantum entanglement, in which particles process and transmit information in parallel.
These systems consist of a large number of fragile parts, which makes them difficult to scale. However, engineers at Harvard have figured out how to place an anologous system on an ultrathin metasurface, which, with the help of nanoholes controls the light as efficiently as larger systems.
Under the leadership of Professor of Applied Physics Federico Capasso and Senior Research Fellow in Electrical Engineering Wynton Hayes, a team of researchers from Harvard’s John A. Paulson School of Engineering and Applied Science (SEAS) has developed specialized metasurfaces that serve as a compact replacement for traditional quantum optical systems. The researchers have demonstrated that metasurfaces are capable of generating entangled photon states and performing complex quantum operations in the same way as larger optical systems that use a large number of components.
«We get a serious technological advantage in solving the scalability problem. Now we can reduce the entire optical setup into a single metasurface that is highly stable and reliable», — explains the first author of the study Carolos Yousef.
The obtained results demonstrate the possibility of creating revolutionary quantum devices that will not be based on traditional hard-to-scale components, in particular, waveguides and light guides, and not even on advanced optical microchips, but on error-resistant metasurfaces that have many advantages: designs that do not require complex setup, resistance to disturbances, cost-effectiveness, ease of manufacture, and low optical losses.
Developing a metasurface that would precisely control properties such as brightness, phase, and polarization was a mathematically challenging task. The difficulty arose as the number of photons and, consequently, qubits increased. Each new photon creates a large number of new paths interference, which in a traditional system would require a rapidly growing number of light guides and output ports.
To organize this complex system, the researchers used the mathematical theory of graphs. This theory uses points and lines to show connections and relationships. By representing the entangled states of photons as many connected lines and dots, they were able to visually determine how photons interact with each other and predict their effects in experiments. The finished study was the result of cooperation with Marco Lončar’s laboratory, whose team specializes in quantum optics and integrated photonics and provided the necessary expertise and equipment.
«I am inspired by this approach because it allows for efficient scaling of optical quantum computers and networks, which has long been the biggest challenge compared to other platforms such as superconductors or atoms. In a sense, with this approach, metasurface design and the optical quantum state become two sides of the same coin», — researcher Neil Sinclair.
The results of the study are published in the journal Science
Source: SciTechDaily
Spelling error report
The following text will be sent to our editors: