| Project/Area Number |
22K14623
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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| Review Section |
Basic Section 30020:Optical engineering and photon science-related
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| Research Institution | Institute of Physical and Chemical Research |
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Principal Investigator |
Fong CheeFai 国立研究開発法人理化学研究所, 開拓研究本部, 基礎科学特別研究員 (30881544)
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| Project Period (FY) |
2022-04-01 – 2025-03-31
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| Project Status |
Granted (Fiscal Year 2023)
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| Budget Amount *help |
¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000)
Fiscal Year 2023: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
Fiscal Year 2022: ¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000)
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| Keywords | 2D materials device / Photonic crystal / Optics and photonics / photonic crystal / optics and photonics / Valley spin devices / semiconductor / layered material |
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| Outline of Research at the Start |
In 2D semiconductors, the electron and holes possess coupled valley and spin properties which are referred to as valley spin. We propose the demonstration of valley spin devices by coupling 2D semiconductors to novel circularly polarized chiral photonic crystal nanocavities.
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| Outline of Annual Research Achievements |
Using the photonic crystal (PhC) and 2D materials transfer technologies that we have developed previously, in this fiscal year, we have been focused on studying the self-aligned hybrid nanocavities. These hybrid nanocavities are formed by partially covering a photonic crystal waveguide post-fabrication with a suitably-sized 2D material flake. The presence of the flake increases the local refractive index causing a frequency mismatch of the optical fields in the regions with and without the flake results in the formation of a nanocavity. We successfully fabricated such hybrid nanocavity devices with hBN, WSe2 and MoTe2 flakes on silicon PhC waveguides.
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| Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
In our hybrid nanocavity devices, we have obtained Q factors as high as 4.0×10^5. Remarkably, even monolayer flakes can provide sufficient local refractive index modulation to induce high Q nanocavity formation. We have also managed to observe cavity PL enhancement in a self-aligned MoTe2 cavity device, with a cavity Purcell enhancement factor of about 15. Our results highlight the potential of our devices to enhance light-matter coupling and to create functional optical devices.
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| Strategy for Future Research Activity |
So far, we have fabricated hybrid nanocavities using a single flake per device. One of the key features of 2D materials is their amenability to heterogenous stacking i.e. stacking of 2D materials with different compositions and atomic lattices without having to worry about lattice matching. Such heterogeneous stacking has been used as encapsulation or passivation layer to sandwich and protect the 2D materials. Following from our results, our next step will be focused on coupling heterogenous stack of materials to the self-aligned hybrid nanocavities.
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