2022 Fiscal Year Research-status Report
Demonstration of valley spin devices by coupling 2D semiconductors to chiral photonic crystal nanocavities
| Project/Area Number |
22K14623
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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 – 2024-03-31
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| Keywords | 2D materials device / photonic crystal / optics and photonics |
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| Outline of Annual Research Achievements |
Based on our simulation results, we have fabricated H1 photonic crystal (PhC) cavities with silicon and characterized their optical characteristics by measuring the photoluminescence (PL) from the cavity. From our measurement results, the cavity resonant wavelengths and quality factor are consistent with our numerical simulations. In principle, the H1 PhC cavity has two degenerate dipole modes. However, as fabrication errors are avoidable, the spectral degeneracy of the modes are lifted resulting in the observation of two peaks in the PL spectra. The magnitude of the peak splitting varies from cavity to cavity. Results from our current sample will be used as feedback for our next fabrication in order to reduce fabrication error and thus improve the mode degeneracies.
On the other hand, we intend to heterogeneously integrate 2D van der Waals material on the photonic crystal. We have further developed the technologies related to 2D materials. In particular, we carried out 2D materials exfoliation and transfer using combinations of polydimethylsiloxane (PDMS), anthracene and hexagonal boron nitride (hBN) flakes.
We also developed a novel type of photonic crystal cavity, namely the 2D material-induced nanocavity in a photonic crystal waveguide. A 2D material flake of a suitable width can provide a small local refractive index modulation to induce the formation of a cavity in a PhC waveguide at wherever the 2D material is placed. We confirmed the feasibility of such method by FDTD and FEM simulations.
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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
We fabricated the H1 photonic crystal cavity samples as planned and characterized their optical properties, using the results as feedback to improved the nanofabrication and optical properties. To achieve our research goal of heterogeneously integrating 2D materials on the photonic crystal cavity, we have further advanced our 2D materials transfer techniques which now uses combinations of polydimethylsiloxane (PDMS), anthracene and hexagonal boron nitride (hBN) flakes. We also developed a novel type of photonic crystal cavity, namely the 2D material-induced nanocavity in a photonic crystal waveguide.
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| Strategy for Future Research Activity |
We will continue to fabricate photonic crystal samples, using our existing results as guidance to improve the quality of the fabricated samples. We also plan to further investigate the reliability and consistency of our 2D materials dry transfer technique. Further research effort will be put in to investigate the optical properties of the novel 2D material-induced nanocavity, focusing on how the types of 2D materials affect the quality of the cavity, as well as the functionality of the nanocavity devices.
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| Causes of Carryover |
Minor adjustments according to research progress. The funds will be used for consumables, publishing fee and travel expenses.
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