Researchers have developed a pioneering multi-functional device that could pave the way for advanced quantum applications, including larger and more complex quantum computers and networks.
Realizing the Promise of Color Centers in Solid-State
So far stable solid-state color centers may constitute good qubit nodes, fundamental units for storing and processing quantum information. These point defects are able to absorb and emit light at specific wavelengths, which makes them important for practical quantum applications.
Whilst promising in principle, these colour centres can only be made use of if they are conveniently optical accessible and smoothly controllable at high speeds, tuned to the desired optical transition frequencies and available for the coherent manipulation of their spins. Their new device, however, fulfills all of these demands simultaneously and is based on a scalable (and cryogenically-compatible) platform.
Flexible, robust platform
Designed by researchers as part of MITRE’s Quantum Moonshot program, the cryo-integrated system-on-chip device incorporates tin vacancy color centers. The optical emission of these color centers is coupled to the diamond nanowaveguides lying on chip, and in this work we use them for manipulation of the optical and spin transitions of qubits.
These include on-chip microwave lines to control the quantum state of qubits and active cantilevers that can induce mechanical strain, modifying the electronic and optical properties of embedded spin centers. Besides, a high-speed piezo actuator is integrated into the multi-channel atom-control photonic integrated circuit for programmable independent optical excitation of multiple qubits simultaneously.
Here, we show that this versatile platform can support high extinction (> 35 dB) and high-speed (> 30 MHz) optical switching with low crosstalk (< 1 % of total on–off signal), which in turn will allow multiple qubit nodes to be individually excited and probed strain-free and microwaves along independent channels to control adjacent QEs.
Conclusion
The new paper is part of a broader effort to make large-scale quantum technologies practical by building, step-by-step and component-by-component, easily-manufactured pieces that actually work as they should. With all required functionality on an integrated cryogenically compatible platform, the researchers have set the stage for subsequent technological advancements in quantum computation and communication, devices beyond superconducting qubits and even possibly a spin-based quantum computer. Through the continued integration of these color center qubit control devices with on-chip photonics, they are looking to realize a completely scalable platform for quantum information processing, pushing toward an eventual end-to-end demonstration of a new class of technology that was previously seen as unobtainable.
