2022-09-12 サンディア国立研究所(SNL)
Green laser light illuminates a metasurface that is a hundred times thinner than paper, that was fabricated at the Center for Integrated Nanotechnologies. CINT is jointly operated by Sandia and Los Alamos national laboratories for the Department of Energy Office of Science. (Photo by Craig Fritz) Click on the thumbnail for a high-resolution image.
このデバイスは、メタサーフェスと呼ばれる一種のナノ工学材料で、これまで小型の技術では不可能だった複雑な方法で光子を絡め取る道を開くものである。
サイエンスの論文は、チームがメタサーフェスを調整して、さまざまな波長の絡み合った光子を生成することに成功した方法を概説しており、これは複雑に絡み合った光子のいくつかのペアを同時に生成するための重要な先駆者です。
しかし、研究者らは論文の中で、デバイスの効率(絡み合った光子のグループを生成する速度)は他の技術の効率よりも低く、改善する必要があると指摘しています。
＜関連情報＞
- https://newsreleases.sandia.gov/quantum_metasurface/
- https://www.science.org/doi/10.1126/science.abq8684
複雑な量子状態を生成するための共振メタサーフェス Resonant metasurfaces for generating complex quantum states
Tomás Santiago-Cruz,Sylvain D. Gennaro,Oleg Mitrofanov,Sadhvikas Addamane,John Reno,Igal Brener,Maria V. Chekhova
Science Published:25 Aug 2022
DOI: 10.1126/science.abq8684
Quantum metasurfaces
Metasurfaces are specially designed arrays of dielectric components that transform the function of bulk optical components into thin films. Exploiting the physics of bound states in the continuum for the highly efficient trapping of light, Santiago-Cruz et al. design and fabricate metasurfaces that can operate as quantum sources of light. Patterned in GaAs, the quantum source provides entangled pairs of photons across a broad range of wavelength, allowing the formation of complex quantum states. The approach will be useful for the development of integrated optical and quantum optical devices. —ISO
Abstract
Quantum state engineering, the cornerstone of quantum photonic technologies, mainly relies on spontaneous parametric downconversion and four-wave mixing, where one or two pump photons spontaneously decay into a photon pair. Both of these nonlinear effects require momentum conservation for the participating photons, which strongly limits the versatility of the resulting quantum states. Nonlinear metasurfaces have subwavelength thickness and allow the relaxation of this constraint; when combined with resonances, they greatly expand the possibilities of quantum state engineering. Here, we generated entangled photons via spontaneous parametric downconversion in semiconductor metasurfaces with high–quality factor, quasi-bound state in the continuum resonances. By enhancing the quantum vacuum field, our metasurfaces boost the emission of nondegenerate entangled photons within multiple narrow resonance bands and over a wide spectral range. A single resonance or several resonances in the same sample, pumped at multiple wavelengths, can generate multifrequency quantum states, including cluster states. These features reveal metasurfaces as versatile sources of complex states for quantum information.
