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Updated: Jun 24, 2025
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Spectral and Angle-Resolved Magneto-Optical Characterization of Photonic Nanostructures
Published on: November 21, 2019
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Isotopic effects on in-plane hyperbolic phonon polaritons in MoO3
Jeremy F Schultz1, Sergiy Krylyuk2, Jeffrey J Schwartz3
1Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
Nanophotonics (Berlin, Germany)
|June 7, 2024
Summary
Isotopically enriched molybdenum trioxide crystals offer tunable control over hyperbolic phonon polaritons (HPhPs). This tuning is crucial for advancing nanophotonic applications by manipulating light confinement and propagation.
Area of Science:
- Condensed Matter Physics
- Nanophotonics
- Materials Science
Background:
- Hyperbolic phonon polaritons (HPhPs) are light-vibration hybrids in polar dielectrics, enabling nanoscale light manipulation.
- Molybdenum trioxide (α-MoO3) is a natural hyperbolic material where dielectric properties dictate HPhP propagation.
- Existing strategies to tune HPhPs include substrate engineering, nano/heterostructuring, and isotopic enrichment.
Purpose of the Study:
- To investigate the effect of isotopic enrichment on the properties and dispersion of hyperbolic phonon polaritons (HPhPs) in α-MoO3.
- To explore isotopic enrichment as a method for fine-tuning HPhP behavior for nanophotonic applications.
Main Methods:
- Synthesis of isotopically enriched 92MoO3 and 100MoO3 crystals.
- Real-space, near-field mapping using the photothermal induced resonance (PTIR) technique.
- Comparison of HPhP properties in enriched crystals versus natural α-MoO3 within the reststrahlen band (≈820–972 cm-1).
Main Results:
- Isotopic enrichment significantly alters the dielectric function of α-MoO3.
- HPhP dispersion shifts by ≈-7% for 92MoO3 and ≈+9% for 100MoO3.
- HPhP group velocities change by ≈ ±12%, with lifetimes slightly improved (≈20%) in 92MoO3 due to reduced isotopic disorder.
Conclusions:
- Isotopic enrichment provides a precise method to tune HPhP dispersion and propagation characteristics in α-MoO3.
- Reduced isotopic disorder in enriched samples can lead to improved phonon polariton lifetimes.
- This control over HPhP properties is essential for developing advanced nanophotonic devices.
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