Quantum Dot-Induced Blue Shift of Surface Plasmon Spectroscopy
We experimentally demonstrate the spectral blue shift of surface plasmon resonance through the resonant coupling between quantum dots (QDs) and surface plasmons, surprisingly in contrast to the conventionally observed red shift of plasmon spectroscopy. Multimode optical fibers are used for extended...
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MDPI AG
2022-06-01
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| Series: | Nanomaterials |
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| Online Access: | https://www.mdpi.com/2079-4991/12/12/2076 |
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| author | Than Thi Nguyen Vien Thi Tran Joo Seon Seok Jun-Ho Lee Heongkyu Ju |
| author_facet | Than Thi Nguyen Vien Thi Tran Joo Seon Seok Jun-Ho Lee Heongkyu Ju |
| author_sort | Than Thi Nguyen |
| collection | DOAJ |
| description | We experimentally demonstrate the spectral blue shift of surface plasmon resonance through the resonant coupling between quantum dots (QDs) and surface plasmons, surprisingly in contrast to the conventionally observed red shift of plasmon spectroscopy. Multimode optical fibers are used for extended resonant coupling of surface plasmons with excited states of QDs adsorbed to the plasmonic metal surface. The long-lived nature of excited QDs permits QD-induced negative change in the local refractive index near the plasmonic metal surface to cause such a blue shift. The analysis utilizes the physical causality-driven optical dispersion relation, the Kramers–Kronig (KK) relation, attempting to understand the abnormal behavior of the QDs-induced index dispersion extracted from blue shift measurement. Properties of QDs’ gain spectrally resonating with plasmons can account for such blue shift, though their absorbance properties never allow the negative index change for the blue shift observed according to the KK relation. We also discuss the limited applicability of the KK relation and possible QDs gain saturation for the experiment–theory disagreement. This work may contribute to the understanding of the photophysical properties critical for plasmonic applications, such as plasmonic local index engineering required in analyte labeling QDs coupled with plasmons for biomedical imaging or assay. |
| first_indexed | 2024-03-09T22:51:56Z |
| format | Article |
| id | doaj.art-0d32fda3e5aa4df0b56cc1772f888d41 |
| institution | Directory Open Access Journal |
| issn | 2079-4991 |
| language | English |
| last_indexed | 2024-03-09T22:51:56Z |
| publishDate | 2022-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Nanomaterials |
| spelling | doaj.art-0d32fda3e5aa4df0b56cc1772f888d412023-11-23T18:17:07ZengMDPI AGNanomaterials2079-49912022-06-011212207610.3390/nano12122076Quantum Dot-Induced Blue Shift of Surface Plasmon SpectroscopyThan Thi Nguyen0Vien Thi Tran1Joo Seon Seok2Jun-Ho Lee3Heongkyu Ju4Department of Physics, Gachon University, Seongnam 13120, KoreaDepartment of Physics, Gachon University, Seongnam 13120, KoreaDepartment of Physics, Gachon University, Seongnam 13120, KoreaLaser & Opto-Electronics Team, Korea Electronics Technology Institute (KETI), Seongnam 13509, KoreaDepartment of Physics, Gachon University, Seongnam 13120, KoreaWe experimentally demonstrate the spectral blue shift of surface plasmon resonance through the resonant coupling between quantum dots (QDs) and surface plasmons, surprisingly in contrast to the conventionally observed red shift of plasmon spectroscopy. Multimode optical fibers are used for extended resonant coupling of surface plasmons with excited states of QDs adsorbed to the plasmonic metal surface. The long-lived nature of excited QDs permits QD-induced negative change in the local refractive index near the plasmonic metal surface to cause such a blue shift. The analysis utilizes the physical causality-driven optical dispersion relation, the Kramers–Kronig (KK) relation, attempting to understand the abnormal behavior of the QDs-induced index dispersion extracted from blue shift measurement. Properties of QDs’ gain spectrally resonating with plasmons can account for such blue shift, though their absorbance properties never allow the negative index change for the blue shift observed according to the KK relation. We also discuss the limited applicability of the KK relation and possible QDs gain saturation for the experiment–theory disagreement. This work may contribute to the understanding of the photophysical properties critical for plasmonic applications, such as plasmonic local index engineering required in analyte labeling QDs coupled with plasmons for biomedical imaging or assay.https://www.mdpi.com/2079-4991/12/12/2076resonant couplingquantum dotsurface plasmonactive mediumKramers–Kronig relationoptical dispersion |
| spellingShingle | Than Thi Nguyen Vien Thi Tran Joo Seon Seok Jun-Ho Lee Heongkyu Ju Quantum Dot-Induced Blue Shift of Surface Plasmon Spectroscopy Nanomaterials resonant coupling quantum dot surface plasmon active medium Kramers–Kronig relation optical dispersion |
| title | Quantum Dot-Induced Blue Shift of Surface Plasmon Spectroscopy |
| title_full | Quantum Dot-Induced Blue Shift of Surface Plasmon Spectroscopy |
| title_fullStr | Quantum Dot-Induced Blue Shift of Surface Plasmon Spectroscopy |
| title_full_unstemmed | Quantum Dot-Induced Blue Shift of Surface Plasmon Spectroscopy |
| title_short | Quantum Dot-Induced Blue Shift of Surface Plasmon Spectroscopy |
| title_sort | quantum dot induced blue shift of surface plasmon spectroscopy |
| topic | resonant coupling quantum dot surface plasmon active medium Kramers–Kronig relation optical dispersion |
| url | https://www.mdpi.com/2079-4991/12/12/2076 |
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