Quantum Photon

Optical switching technology holds great promise for many applications but hot operating temperatures have been a key obstacle slowing progress. Now, a new optical switching device that can operate at room temperatures and achieve one trillion operations per second has been developed by researchers from IBM and the Skolkovo Institute of Science and Technology.

Writing in Nature last month the researchers report, “[R]ecent progress in nanotechnology and single-molecule spectroscopy paves the way for emergent cost-effective organic quantum optical technologies with potential applications in useful devices operating at ambient conditions…[The new work] opens new horizons for practical implementations like sub-picosecond switching, amplification and all-optical logic at the fundamental quantum limit.”

There’s a brief account of the work posted on IEEE Spectrum. Here’s an excerpt:

“The new device relies on a 35-nanometer-wide organic semiconductor polymer film sandwiched between two highly reflective mirrors. The result is a microscopic cavity designed to keep incoming light trapped inside for as long as possible to help it couple with the cavity’s material.

“Two lasers help operate the device—a bright pump laser and a very weak seed laser. When the pump laser shines on the microcavity, its photons can couple strongly with excitons (electrons bound to their positively charged counterparts, holes) within the cavity’s material. This can give rise to short-lived quasiparticles known as exciton-polaritons.

“The cluster of exciton-polaritons can form so-called Bose-Einstein condensates, collections of particles that each behave like a single atom. The light from the seed beam could switch this condensate between two measurable states that serve as zero and one.”

The study’s senior author Pavlos Lagoudakis, a physicist at the Skolkovo Institute of Science and Technology in Moscow, is quoted in the IEEE Spectrum article, “The most surprising finding was that we could trigger the optical switch with the smallest amount of light, a single photon.” The switching speed is far faster – 100x to 1000x – than commercial transistors.

Here is a bit more detail from the abstract in their paper (Single-photon nonlinearity at room temperature):

“We harness a π-conjugated ladder-type polymer strongly coupled to a microcavity forming hybrid light–matter states, so-called exciton-polaritons, to create exciton-polariton condensates with quantum fluid properties. Obeying Bose statistics, exciton-polaritons exhibit an extreme nonlinearity when undergoing bosonic stimulation, which we have managed to trigger at the single-photon level, thereby providing an efficient way for all-optical ultrafast control over the macroscopic condensate wavefunction. Here, we utilize stable excitons dressed with high-energy molecular vibrations, allowing for single-photon nonlinear operation at ambient conditions.”

In the IEEE Spectrum article, Lagoudakis noted that all-optical-computers are still years away, but said the new research could lead to “optical accelerators” relatively soon—optical computing devices that can perform specialized operations much faster than classical electronic computers. “These could be used to remove computational bottlenecks in supercomputers that usually rely on massive parallel processing,” he said in the article.

Link to paper, https://www.nature.com/articles/s41586-021-03866-9

Link to IEEE Spectrum article, https://spectrum.ieee.org/optical-switch-1000x-faster-transistors

Source: HPC Wire | Found here...

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