Brongersma Group Plasmonics and Photonics at Stanford University

@article{guarneri2024temperature,

title = {Temperature-Dependent Excitonic Light Manipulation with Atomically Thin Optical Elements},

author = {Ludovica Guarneri and Qitong Li and Thomas Bauer and Jung-Hwan Song and Ashley P Saunders and Fang Liu and Mark L Brongersma and Jorik van de Groep},

doi = {10.1021/acs.nanolett.4c00694},

year  = {2024},

date = {2024-04-05},

journal = {Nano Letters},

abstract = {Monolayer 2D semiconductors, such as WS2, exhibit uniquely strong light\textendashmatter interactions due to exciton resonances that enable atomically thin optical elements. Similar to geometry-dependent plasmon and Mie resonances, these intrinsic material resonances offer coherent and tunable light scattering. Thus far, the impact of the excitons’ temporal dynamics on the performance of such excitonic metasurfaces remains unexplored. Here, we show how the excitonic decay rates dictate the focusing efficiency of an atomically thin lens carved directly out of exfoliated monolayer WS2. By isolating the coherent exciton radiation from the incoherent background in the focus of the lens, we obtain a direct measure of the role of exciton radiation in wavefront shaping. Furthermore, we investigate the influence of exciton\textendashphonon scattering by characterizing the focusing efficiency as a function of temperature, demonstrating an increased optical efficiency at cryogenic temperatures. Our results provide valuable insights into the role of excitonic light scattering in 2D nanophotonic devices.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{kuznetsov2024roadmap,

title = {Roadmap for Optical Metasurfaces},

author = {Arseniy I Kuznetsov and Mark L Brongersma and Jin Yao and Mu Ku Chen and Uriel Levy and Din Ping Tsai and Nikolay I Zheludev and Andrei Faraon and Amir Arbabi and Nanfang Yu and Debashis Chanda and Kenneth B Crozier and Alexander V Kildishev and Hao Wang and Joel KW Yang and Jason G Valentine and Patrice Genevet and Jonathan A Fan and Owen D Miller and Arka Majumdar and Johannes E Fr\"{o}ch and David Brady and Felix Heide and Ashok Veeraraghavan and Nader Engheta and Andrea Al\`{u} and Albert Polman and Harry A Atwater and Prachi Thureja and Ramon Paniagua-Dominguez and Son Tung Ha and Angela I Barreda and Jon A Schuller and Isabelle Staude and Gustavo Grinblat and Yuri Kivshar and Samuel Peana and Susanne F Yelin and Alexander Senichev and Vladimir M Shalaev and Soham Saha and Alexandra Boltasseva and Junsuk Rho and Dong Kyo Oh and Joohoon Kim and Junghyun Park and Robert Devlin and Ragip A Pala},

doi = {10.1021/acsphotonics.3c00457},

year  = {2024},

date = {2024-02-27},

journal = {ACS photonics},

volume = {11},

issue = {3},

pages = {816-865},

abstract = {Metasurfaces have recently risen to prominence in optical research, providing unique functionalities that can be used for imaging, beam forming, holography, polarimetry, and many more, while keeping device dimensions small. Despite the fact that a vast range of basic metasurface designs has already been thoroughly studied in the literature, the number of metasurface-related papers is still growing at a rapid pace, as metasurface research is now spreading to adjacent fields, including computational imaging, augmented and virtual reality, automotive, display, biosensing, nonlinear, quantum and topological optics, optical computing, and more. At the same time, the ability of metasurfaces to perform optical functions in much more compact optical systems has triggered strong and constantly growing interest from various industries that greatly benefit from the availability of miniaturized, highly functional, and efficient optical components that can be integrated in optoelectronic systems at low cost. This creates a truly unique opportunity for the field of metasurfaces to make both a scientific and an industrial impact. The goal of this Roadmap is to mark this “golden age” of metasurface research and define future directions to encourage scientists and engineers to drive research and development in the field of metasurfaces toward both scientific excellence and broad industrial adoption.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{doshi2024direct,

title = {Direct electron beam patterning of electro-optically active PEDOT: PSS},

author = {Siddharth Doshi and Dominik Ludescher and Julian Karst and Moritz Floess and Johan Carlstr\"{o}m and Bohan Li and Nofar Mintz Hemed and Yi-Shiou Duh and Nicholas A Melosh and Mario Hentschel and Mark Brongersma and Harald Giessen},

doi = {10.1515/nanoph-2023-0640},

year  = {2024},

date = {2024-01-04},

urldate = {2023-09-12},

journal = {Nanophotonics},

number = {0},

abstract = {The optical and electronic tunability of the conductive polymer poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) has enabled emerging applications as diverse as bioelectronics, flexible electronics, and micro- and nano-photonics. High-resolution spatial patterning of PEDOT:PSS opens up opportunities for novel active devices in a range of fields. However, typical lithographic processes require tedious indirect patterning and dry etch processes, while solution-processing methods such as ink-jet printing have limited spatial resolution. Here, we report a method for direct write nano-patterning of commercially available PEDOT:PSS through electron-beam induced solubility modulation. The written structures are water stable and maintain the conductivity as well as electrochemical and optical properties of PEDOT:PSS, highlighting the broad utility of our method. We demonstrate the potential of our strategy by preparing prototypical nano-wire structures with feature sizes down to 250 nm, an order of magnitude finer than previously reported direct write methods, opening the possibility of writing chip-scale microelectronic and optical devices. We finally use the high-resolution writing capabilities to fabricate electrically-switchable optical diffraction gratings. We show active switching in this archetypal system with \>95 % contrast at CMOS-compatible voltages of +2 V and −3 V, offering a route towards highly-miniaturized dynamic optoelectronic devices.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@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}

}