Isotopic effects on in-plane hyperbolic phonon polaritons in MoO3
Hyperbolic phonon polaritons (HPhPs), hybrids of light and lattice vibrations in polar dielectric crystals, empower nanophotonic applications by enabling the confinement and manipulation of light at the nanoscale. Molybdenum trioxide (α-MoO3) is a naturally hyperbolic material, meaning that its diel...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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De Gruyter
2024-03-01
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| Series: | Nanophotonics |
| Subjects: | |
| Online Access: | https://doi.org/10.1515/nanoph-2023-0717 |
| _version_ | 1827113762104016896 |
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| author | Schultz Jeremy F. Krylyuk Sergiy Schwartz Jeffrey J. Davydov Albert V. Centrone Andrea |
| author_facet | Schultz Jeremy F. Krylyuk Sergiy Schwartz Jeffrey J. Davydov Albert V. Centrone Andrea |
| author_sort | Schultz Jeremy F. |
| collection | DOAJ |
| description | Hyperbolic phonon polaritons (HPhPs), hybrids of light and lattice vibrations in polar dielectric crystals, empower nanophotonic applications by enabling the confinement and manipulation of light at the nanoscale. Molybdenum trioxide (α-MoO3) is a naturally hyperbolic material, meaning that its dielectric function deterministically controls the directional propagation of in-plane HPhPs within its reststrahlen bands. Strategies such as substrate engineering, nano- and hetero-structuring, and isotopic enrichment are being developed to alter the intrinsic dielectric functions of natural hyperbolic materials and to control the confinement and propagation of HPhPs. Since isotopic disorder can limit phonon-based processes such as HPhPs, here we synthesize isotopically enriched 92MoO3 (92Mo: 99.93 %) and 100MoO3 (100Mo: 99.01 %) crystals to tune the properties and dispersion of HPhPs with respect to natural α-MoO3, which is composed of seven stable Mo isotopes. Real-space, near-field maps measured with the photothermal induced resonance (PTIR) technique enable comparisons of in-plane HPhPs in α-MoO3 and isotopically enriched analogs within a reststrahlen band (≈820 cm−1 to ≈972 cm−1). Results show that isotopic enrichment (e.g., 92MoO3 and 100MoO3) alters the dielectric function, shifting the HPhP dispersion (HPhP angular wavenumber × thickness vs. IR frequency) by ≈−7 % and ≈+9 %, respectively, and changes the HPhP group velocities by ≈±12 %, while the lifetimes (≈3 ps) in 92MoO3 were found to be slightly improved (≈20 %). The latter improvement is attributed to a decrease in isotopic disorder. Altogether, isotopic enrichment was found to offer fine control over the properties that determine the anisotropic in-plane propagation of HPhPs in α-MoO3, which is essential to its implementation in nanophotonic applications. |
| first_indexed | 2024-04-24T06:46:55Z |
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| id | doaj.art-b88f0ea1572d4b7b8c33f2f85960e85a |
| institution | Directory Open Access Journal |
| issn | 2192-8614 |
| language | English |
| last_indexed | 2025-03-20T11:51:08Z |
| publishDate | 2024-03-01 |
| publisher | De Gruyter |
| record_format | Article |
| series | Nanophotonics |
| spelling | doaj.art-b88f0ea1572d4b7b8c33f2f85960e85a2024-09-16T09:44:09ZengDe GruyterNanophotonics2192-86142024-03-011391581159210.1515/nanoph-2023-0717Isotopic effects on in-plane hyperbolic phonon polaritons in MoO3Schultz Jeremy F.0Krylyuk Sergiy1Schwartz Jeffrey J.2Davydov Albert V.3Centrone Andrea4Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD20899, USAMaterial Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD20899, USAPhysical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD20899, USAMaterial Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD20899, USAPhysical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD20899, USAHyperbolic phonon polaritons (HPhPs), hybrids of light and lattice vibrations in polar dielectric crystals, empower nanophotonic applications by enabling the confinement and manipulation of light at the nanoscale. Molybdenum trioxide (α-MoO3) is a naturally hyperbolic material, meaning that its dielectric function deterministically controls the directional propagation of in-plane HPhPs within its reststrahlen bands. Strategies such as substrate engineering, nano- and hetero-structuring, and isotopic enrichment are being developed to alter the intrinsic dielectric functions of natural hyperbolic materials and to control the confinement and propagation of HPhPs. Since isotopic disorder can limit phonon-based processes such as HPhPs, here we synthesize isotopically enriched 92MoO3 (92Mo: 99.93 %) and 100MoO3 (100Mo: 99.01 %) crystals to tune the properties and dispersion of HPhPs with respect to natural α-MoO3, which is composed of seven stable Mo isotopes. Real-space, near-field maps measured with the photothermal induced resonance (PTIR) technique enable comparisons of in-plane HPhPs in α-MoO3 and isotopically enriched analogs within a reststrahlen band (≈820 cm−1 to ≈972 cm−1). Results show that isotopic enrichment (e.g., 92MoO3 and 100MoO3) alters the dielectric function, shifting the HPhP dispersion (HPhP angular wavenumber × thickness vs. IR frequency) by ≈−7 % and ≈+9 %, respectively, and changes the HPhP group velocities by ≈±12 %, while the lifetimes (≈3 ps) in 92MoO3 were found to be slightly improved (≈20 %). The latter improvement is attributed to a decrease in isotopic disorder. Altogether, isotopic enrichment was found to offer fine control over the properties that determine the anisotropic in-plane propagation of HPhPs in α-MoO3, which is essential to its implementation in nanophotonic applications.https://doi.org/10.1515/nanoph-2023-07172d materialshyperbolic materialsisotopic engineeringphonon polaritonsphotothermal induced resonance |
| spellingShingle | Schultz Jeremy F. Krylyuk Sergiy Schwartz Jeffrey J. Davydov Albert V. Centrone Andrea Isotopic effects on in-plane hyperbolic phonon polaritons in MoO3 Nanophotonics 2d materials hyperbolic materials isotopic engineering phonon polaritons photothermal induced resonance |
| title | Isotopic effects on in-plane hyperbolic phonon polaritons in MoO3 |
| title_full | Isotopic effects on in-plane hyperbolic phonon polaritons in MoO3 |
| title_fullStr | Isotopic effects on in-plane hyperbolic phonon polaritons in MoO3 |
| title_full_unstemmed | Isotopic effects on in-plane hyperbolic phonon polaritons in MoO3 |
| title_short | Isotopic effects on in-plane hyperbolic phonon polaritons in MoO3 |
| title_sort | isotopic effects on in plane hyperbolic phonon polaritons in moo3 |
| topic | 2d materials hyperbolic materials isotopic engineering phonon polaritons photothermal induced resonance |
| url | https://doi.org/10.1515/nanoph-2023-0717 |
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