16.08.2021 • News

Improved single photon switch

A first step towards realizing chip-scale scalable single photon switches.

The ability to turn on and off a physical process with just one photon is a funda­mental building block for quantum photonic techno­logies. Realizing this in a chip-scale archi­tecture is important for scalability, which ampli­fies a break­through by City College of New York researchers led by physicist Vinod Menon. They've demons­trated for the first time the use of Rydberg states in solid state materials to enhance nonlinear optical interactions to unprecedented levels in solid state systems. This feat is a first step towards rea­lizing chip-scale scalable single photon switches. 

Schematic of the optical micro­cavity with 2D semi­conductor. The nonlinear...
Schematic of the optical micro­cavity with 2D semi­conductor. The nonlinear optical response arises from the larger Bohr radii Rydberg excitons allowing to push the limit to few photon non­linear limit. (Source: R. Bushati)

In solid state systems, exciton-polaritons, half-light half-matter quasi­particles, which result from the hybridi­zation of elec­tronic excitations and photons, are an attractive candidate to realize nonlineari­ties at the quantum limit. “Here we realize these quasi­particles with Rydberg excitons in atomically thin semi­conductors,” said Menon, chair of physics in City College's Division of Science. “Excited states of excitons owing to their larger size, show enhanced inter­actions and therefore hold promise for accessing the quantum domain of single-photon non­linearities, as demons­trated previously with Rydberg states in atomic systems.” 

According to Menon, the demons­tration of Rydberg exciton-polaritons in two-dimensional semi­conductors and their enhanced nonlinear response presents the first step towards the generation of strong photon inter­actions in solid state systems, a necessary building block for quantum photonic techno­logies. “The research of Menon and his co-workers could have a tremendous impact on Army goals for ultra-low energy information processing and computing for mobile Army platforms such as unmanned systems,” said Michael Gerhold, program manager at the U.S. Army Combat Capa­bilities Development Command, DEVCOM, Army Research Laboratory. “Optical switching and nonlinearities used in future computing paradigms that use photonics would benefit from this advance­ment. Such strong coupling effects would reduce energy consumption and possibly aid computing performance.” (Source: CCNY)

Reference: J. Gu et al.: Enhanced nonlinear interaction of polaritons via excitonic Rydberg states in monolayer WSe2, Nat. Commun. 12, 2269 (2021); DOI: 10.1038/s41467-021-22537-x

Link: Dept. of Physics, City College of New York, New York, USA

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