Quantum State Generation of THz-Light and Exploration of Quantum Measurement Applications

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H03747
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 80040:Quantum beam science-related
• Research Institution: Ishinomaki Senshu University (2022-2023); Institute of Physical and Chemical Research (2021)
• Principal Investigator: NOTAKE TAKASHI 石巻専修大学, 理工学部, 准教授 (70413995)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: テラヘルツ電磁波 / 量子

Outline of Final Research Achievements

Recent quantum research has advanced the quest for the ultimate measurement and has begun to demonstrate that the limits of classical measurement can be broken by extending the interference of light using non-linear optical effects to quantum states.
In the terahertz frequency range, photon detection is in principle difficult because the photon energy is so weak that it corresponds to room temperature thermal fluctuations.To overcome this difficulty, we have attempted to detect ultra-sensitive THz-wave photons using a backward THz-wave parametric oscillation process. Two independent PPLN crystals are used to achieve a quantum conversion with photon energies differing by a factor of 1000.The highly efficient conversion of 300 GHz sub-THz photons into near-infrared photons with a wavelength of 1 um has led to successful detection of terahertz electromagnetic waves at the photon level.

Free Research Field

テラヘルツ光学

Academic Significance and Societal Importance of the Research Achievements

光の量子力学的性質を利用した研究は、光子エネルギーの大きな可視光や近赤外光領域においてのみ進展してきた。この理由は可視光や近赤外光であれば光子エネルギーが大きく、半導体検出器などで容易に光子レベルの超高感度検出が可能となるためである。
可視光領域に比べて光子エネルギーが1000分の１程度のテラヘルツ電磁波に対する量子研究は、光子検出の困難さから進展が非常に立ち遅れている。本研究において、後進パラメトリック過程によりテラヘルツ電磁波を可視光へと高効率に変換することで光子レベルのサブテラヘルツ電磁波検出が可能である事が実証でき、テラヘルツ光子の量子的理解の深化が今後大いに進展する事が期待できる。