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Publications
Skyler P Selvin; Majid Esfandyarpour; Anqi Ji; Yan Joe Lee; Colin Yule; Jung-Hwan Song; Mohammad Taghinejad; Mark L Brongersma
Acoustic wave modulation of gap plasmon cavities Journal Article
In: Science, vol. 389, iss. 6759, pp. 516-520, 2025.
@article{selvin2025acoustic,
title = {Acoustic wave modulation of gap plasmon cavities},
author = {Skyler P Selvin and Majid Esfandyarpour and Anqi Ji and Yan Joe Lee and Colin Yule and Jung-Hwan Song and Mohammad Taghinejad and Mark L Brongersma},
url = {https://brongersma.stanford.edu/wp-content/uploads/2025/08/science.adv1728-2.pdf
https://www.science.org/stoken/author-tokens/ST-2800/full},
doi = {10.1126/science.adv1728},
year = {2025},
date = {2025-07-31},
urldate = {2025-07-31},
journal = {Science},
volume = {389},
issue = {6759},
pages = {516-520},
abstract = {The important role of metallic nanostructures in nanophotonics will expand if ways to electrically manipulate their optical resonances at high speed can be identified. We capitalized on electrically driven surface acoustic waves and the extreme light concentration afforded by gap plasmons to achieve this goal. We placed gold nanoparticles in a particle-on-mirror configuration with a few-nanometer-thick, compressible polymer spacer. Surface acoustic waves were then used to tune light scattering at speeds approaching the gigahertz regime. We observed evidence that the surface acoustic waves produced mechanical deformations in the polymer and that ensuing nonlinear mechanical dynamics led to unexpectedly large levels of strain and spectral tuning. Our approach provides a design strategy for electrically driven dynamic metasurfaces and fundamental explorations of high-frequency, polymer dynamics in ultraconfined geometries.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The important role of metallic nanostructures in nanophotonics will expand if ways to electrically manipulate their optical resonances at high speed can be identified. We capitalized on electrically driven surface acoustic waves and the extreme light concentration afforded by gap plasmons to achieve this goal. We placed gold nanoparticles in a particle-on-mirror configuration with a few-nanometer-thick, compressible polymer spacer. Surface acoustic waves were then used to tune light scattering at speeds approaching the gigahertz regime. We observed evidence that the surface acoustic waves produced mechanical deformations in the polymer and that ensuing nonlinear mechanical dynamics led to unexpectedly large levels of strain and spectral tuning. Our approach provides a design strategy for electrically driven dynamic metasurfaces and fundamental explorations of high-frequency, polymer dynamics in ultraconfined geometries.
Hossein Taghinejad; Mohammad Taghinejad; Sajjad Abdollahramezani; Qitong Li; Eric V Woods; Mengkun Tian; Ali A Eftekhar; Yuanqi Lyu; Xiang Zhang; Pulickel M Ajayan; Wenshan Cai; Mark L Brongersma; James G Analytis; Ali Adibi
Ion-assisted nanoscale material engineering in atomic layers Journal Article
In: Nano Letters, vol. 25, iss. 25, pp. 10123-10130, 2025.
@article{taghinejad2025ion,
title = {Ion-assisted nanoscale material engineering in atomic layers},
author = {Hossein Taghinejad and Mohammad Taghinejad and Sajjad Abdollahramezani and Qitong Li and Eric V Woods and Mengkun Tian and Ali A Eftekhar and Yuanqi Lyu and Xiang Zhang and Pulickel M Ajayan and Wenshan Cai and Mark L Brongersma and James G Analytis and Ali Adibi},
doi = {10.1021/acs.nanolett.5c02040},
year = {2025},
date = {2025-06-13},
urldate = {2025-06-13},
journal = {Nano Letters},
volume = {25},
issue = {25},
pages = {10123-10130},
abstract = {Achieving deterministic control over the properties of low-dimensional materials with nanoscale precision is a long-sought goal. Mastering this capability has a transformative effect on the design of multifunctional electrical and optical devices. Here, we present an ion-assisted synthetic technique that enables precise control over the material composition and energy landscape of two-dimensional (2D) atomic crystals. Our method transforms binary transition-metal dichalcogenides, like MoSe2, into ternary MoS2αSe2(1−α) alloys with systematically adjustable compositions, α. By piecewise assembly of the lateral, compositionally modulated MoS2αSe2(1−α) segments within 2D atomic layers, we present a synthetic pathway toward the realization of multicompositional designer materials. Our technique enables the fabrication of advanced 2D structures with arbitrary boundaries, dimensions as small as 30 nm, and fully customizable energy landscapes. Our optical characterizations further showcase the potential for implementing tailored optoelectronics in these engineered 2D crystals.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Achieving deterministic control over the properties of low-dimensional materials with nanoscale precision is a long-sought goal. Mastering this capability has a transformative effect on the design of multifunctional electrical and optical devices. Here, we present an ion-assisted synthetic technique that enables precise control over the material composition and energy landscape of two-dimensional (2D) atomic crystals. Our method transforms binary transition-metal dichalcogenides, like MoSe2, into ternary MoS2αSe2(1−α) alloys with systematically adjustable compositions, α. By piecewise assembly of the lateral, compositionally modulated MoS2αSe2(1−α) segments within 2D atomic layers, we present a synthetic pathway toward the realization of multicompositional designer materials. Our technique enables the fabrication of advanced 2D structures with arbitrary boundaries, dimensions as small as 30 nm, and fully customizable energy landscapes. Our optical characterizations further showcase the potential for implementing tailored optoelectronics in these engineered 2D crystals.
Mohammad Taghinejad; Chenyi Xia; Martin Hrton; Kyu-Tae Lee; Andrew S Kim; Qitong Li; Burak Guzelturk; Radek Kalousek; Fenghao Xu; Wenshan Cai; Aaron M Lindenberg; Mark L Brongersma
Determining hot-carrier transport dynamics from terahertz emission Journal Article
In: Science, vol. 382, iss. 6668, pp. 299-305, 2023.
@article{taghinejad2023determining,
title = {Determining hot-carrier transport dynamics from terahertz emission},
author = {Mohammad Taghinejad and Chenyi Xia and Martin Hrton and Kyu-Tae Lee and Andrew S Kim and Qitong Li and Burak Guzelturk and Radek Kalousek and Fenghao Xu and Wenshan Cai and Aaron M Lindenberg and Mark L Brongersma},
doi = {10.1126/science.adj5612},
year = {2023},
date = {2023-10-20},
urldate = {2023-10-20},
journal = {Science},
volume = {382},
issue = {6668},
pages = {299-305},
abstract = {Understanding the ultrafast excitation and transport dynamics of plasmon-driven hot carriers is critical to the development of optoelectronics, photochemistry, and solar-energy harvesting. However, the ultrashort time and length scales associated with the behavior of these highly out-of-equilibrium carriers have impaired experimental verification of ab initio quantum theories. Here, we present an approach to studying plasmonic hot-carrier dynamics that analyzes the temporal waveform of coherent terahertz bursts radiated by photo-ejected hot carriers from designer nano-antennas with a broken symmetry. For ballistic carriers ejected from gold antennas, we find an ~11-femtosecond timescale composed of the plasmon lifetime and ballistic transport time. Polarization- and phase-sensitive detection of terahertz fields further grant direct access to their ballistic transport trajectory. Our approach opens explorations of ultrafast carrier dynamics in optically excited nanostructures.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Understanding the ultrafast excitation and transport dynamics of plasmon-driven hot carriers is critical to the development of optoelectronics, photochemistry, and solar-energy harvesting. However, the ultrashort time and length scales associated with the behavior of these highly out-of-equilibrium carriers have impaired experimental verification of ab initio quantum theories. Here, we present an approach to studying plasmonic hot-carrier dynamics that analyzes the temporal waveform of coherent terahertz bursts radiated by photo-ejected hot carriers from designer nano-antennas with a broken symmetry. For ballistic carriers ejected from gold antennas, we find an ~11-femtosecond timescale composed of the plasmon lifetime and ballistic transport time. Polarization- and phase-sensitive detection of terahertz fields further grant direct access to their ballistic transport trajectory. Our approach opens explorations of ultrafast carrier dynamics in optically excited nanostructures.
