2019 Fiscal Year Final Research Report
High-purity massive entaglement generator pumped by incoherent light source such as LED
| Project/Area Number |
18K19029
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| Research Category |
Grant-in-Aid for Challenging Research (Exploratory)
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| Allocation Type | Multi-year Fund |
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| Review Section |
Medium-sized Section 30:Applied physics and engineering and related fields
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| Research Institution | The University of Tokyo |
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Principal Investigator |
FUKATSU SUSUMU 東京大学, 大学院総合文化研究科, 教授 (60199164)
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| Project Period (FY) |
2018-06-29 – 2020-03-31
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| Keywords | インコヒーレント光源 / LED励起 / 自発的パラメトリック下方変換 / 伝令付き単一光子発生 / Hong-Ou-Mandel２光子干渉 / エンタングル光子対発生器 |
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| Outline of Final Research Achievements |
Quantum entanglement is relevant in the fields of quantum physics and quantum information processing, which plays a pivotal role in quantum-enhanced technologies that arguably outperform the classical counterparts. One of the established ways to create entangled photon pairs is spontaneous parametric down-conversion in a second-order nonlinear crystal. However, the trade-off between spectral purity and emission rate raises a concern, which practically limits the pump source to a coherent one such as laser. Here we propose an affordable, high-power incoherent light source like light-emitting diode (LED) for use as the pump source for efficient massive high-purity entanglement generation. Building on the successful heralded single-photon generation under LED pumping in the earlier phase of the project, a Hong-Ou-Mandel two-photon interference experiment was attempted. Highly visible HOM dips due to photon bunching were observed, which promises convenient access to entanglement with LEDs.
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| Free Research Field |
応用量子物理学、物性物理学
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| Academic Significance and Societal Importance of the Research Achievements |
インコヒーレント光源を用いて量子エンタングルメントを生成することは、それ自体が一大技術革新である一方、従来は看過されてきた励起光の干渉性の高さすなわちコヒーレンスのもたらすエンタングルメントの質に関する学理の解明にもつながる。良質のエンタングルメント生成には高励起パワーに加えて大きな結晶が必要とされるが、本研究が目指すインコヒーレント光励起のエンタングルメント光子対生成によって結晶長と励起光コヒーレンスとの不整合の問題が根本的に解消できれば、光源選択の幅が拡がるとともに経済的でコンパクトな大規模並列量子もつれ生成器の実現を初めとしてその恩恵は計り知れない。
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