MIT researchers develop new way to control light and matter

Researchers from MIT and other institutions have made significant progress in developing devices that efficiently bridge the gap between matter and light. This breakthrough could lead to the creation of more efficient computer chips and quantum computers that operate at room temperature.

The team achieved this by creating sandwiches of perovskite flakes between two precisely spaced reflective surfaces. By stimulating these perovskite sandwiches with laser beams, they were able to directly control the momentum of specific quasiparticles known as exciton-polariton pairs, which are hybrids of light and matter. This control over exciton-polaritons could enable the reading and writing of data in devices based on this phenomenon.

Exciton-polaritons lie on a spectrum between electronic and photonic systems, combining the best properties of both. They can be easily controlled through multiple variables, unlike purely electronic or photonic systems, which have their limitations.

The advantage of these quasiparticles is that they can be manipulated in an energy-efficient manner. The combined state of light and neutral charge allows for perturbation with either light or charge, providing additional levers for modulation.

Moreover, the materials used in this research can be easily manufactured using room-temperature, solution-based processing methods. This suggests that once practical systems are designed, large-scale production could be relatively straightforward. However, it is important to note that this work is still in the early stages, with practical applications expected to be realized in 5 to 10 years.

Overall, this development represents a significant step forward in the field of bridging matter and light and has the potential to revolutionize computer chip design and quantum computing.

Perovskites, specifically phenethylammonium lead iodide, have gained significant attention as materials for lightweight and flexible solar photovoltaic panels. The researchers chose this version of perovskite due to its ability to efficiently convert light into electrons or excitons, depending on its properties.

To create an optical cavity capable of trapping photons, the team placed small flakes of the perovskite material between mirrored surfaces. These ultrathin layers, separated by precise spacer layers, allowed for the bouncing of emitted green light between the mirrors. This rapid reabsorption and re-emission of light and excitons resulted in a superposition state, similar to a Bose-Einstein Condensate, where particles behave collectively.

Typically, producing arrays of such condensates requires ultralow cryogenic temperatures. However, perovskites offer the potential to achieve this phenomenon at elevated temperatures. The researchers identified fundamental characteristics of the condensation process and proposed material and device architecture strategies to enable it. This progress could be a crucial step toward developing room-temperature qubits for quantum computing.

While the development of such devices may take several years, the immediate application of these findings could be the production of novel light-emitting devices. These devices could offer controllable directional output and serve as electronically controlled steerable light sources.

In summary, perovskite-based materials and their optical properties hold promise for advancements in solar energy and quantum computing, with potential near-term applications in efficient light-emitting devices.

Source: Massachusetts Institute of Technology

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