Professor in CREOL College of Optics & Photonics at University of Central Florida
Recent news
Publications
Jorik van de Groep; Qitong Li; Jung-Hwan Song; Pieter G Kik; Mark L Brongersma
Impact of substrates and quantum effects on exciton line shapes of 2D semiconductors at room temperature Journal Article
In: Nanophotonics, iss. 0, 2023.
@article{van2023impact,
title = {Impact of substrates and quantum effects on exciton line shapes of 2D semiconductors at room temperature},
author = {Jorik van de Groep and Qitong Li and Jung-Hwan Song and Pieter G Kik and Mark L Brongersma},
doi = {10.1515/nanoph-2023-0193},
year = {2023},
date = {2023-06-20},
urldate = {2023-06-20},
journal = {Nanophotonics},
issue = {0},
abstract = {Exciton resonances in monolayer transition-metal dichalcogenides (TMDs) provide exceptionally strong light\textendashmatter interaction at room temperature. Their spectral line shape is critical in the design of a myriad of optoelectronic devices, ranging from solar cells to quantum information processing. However, disorder resulting from static inhomogeneities and dynamical fluctuations can significantly impact the line shape. Many recent works experimentally evaluate the optical properties of TMD monolayers placed on a substrate and the line shape is typically linked directly to the material’s quality. Here, we highlight that the interference of the substrate and TMD reflections can strongly influence the line shape. We further show how basic, room-temperature reflection measurements allow investigation of the quantum mechanical exciton dynamics by systematically controlling the substrate reflection with index-matching oils. By removing the substrate contribution with properly chosen oil, we can extract the excitonic decay rates including the quantum mechanical dephasing rate. The results provide valuable guidance for the engineering of exciton line shapes in layered nanophotonic systems.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Exciton resonances in monolayer transition-metal dichalcogenides (TMDs) provide exceptionally strong light–matter interaction at room temperature. Their spectral line shape is critical in the design of a myriad of optoelectronic devices, ranging from solar cells to quantum information processing. However, disorder resulting from static inhomogeneities and dynamical fluctuations can significantly impact the line shape. Many recent works experimentally evaluate the optical properties of TMD monolayers placed on a substrate and the line shape is typically linked directly to the material’s quality. Here, we highlight that the interference of the substrate and TMD reflections can strongly influence the line shape. We further show how basic, room-temperature reflection measurements allow investigation of the quantum mechanical exciton dynamics by systematically controlling the substrate reflection with index-matching oils. By removing the substrate contribution with properly chosen oil, we can extract the excitonic decay rates including the quantum mechanical dephasing rate. The results provide valuable guidance for the engineering of exciton line shapes in layered nanophotonic systems.
Jiho Hong; Jorik van de Groep; Nayeun Lee; Soo Jin Kim; Philippe Lalanne; Pieter G. Kik; Mark L. Brongersma
Nonlocal metasurface for circularly polarized light detection Journal Article
In: Optica, vol. 10, no. 1, pp. 134-141, 2023.
@article{Hong:23,
title = {Nonlocal metasurface for circularly polarized light detection},
author = {Jiho Hong and Jorik van de Groep and Nayeun Lee and Soo Jin Kim and Philippe Lalanne and Pieter G. Kik and Mark L. Brongersma},
doi = {10.1364/OPTICA.468252},
year = {2023},
date = {2023-01-20},
journal = {Optica},
volume = {10},
number = {1},
pages = {134-141},
abstract = {Modern-day sensing and imaging applications increasingly rely on accurate measurements of the primary physical quantities associated with light waves: intensity, wavelength, directionality, and polarization. These are conventionally performed with a series of bulky optical elements, but recently, it has been recognized that optical resonances in nanostructures can be engineered to achieve selective photodetection of light waves with a specific set of predetermined properties. Here, we theoretically illustrate how a thin silicon layer can be patterned into a dislocated nanowire-array that affords detection of circularly polarized light with an efficiency that reaches the theoretical limit for circular dichroism of a planar detector in a symmetric external environment. The presence of a periodic arrangement of dislocations is essential in achieving such unparalleled performance as they enable selective excitation of nonlocal, guided-mode resonances for one handedness of light. We also experimentally demonstrate compact, high-performance chiral photodetectors created from these dislocated nanowire-arrays. This work highlights the critical role defects can play in enabling new nanophotonic functions and devices.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Modern-day sensing and imaging applications increasingly rely on accurate measurements of the primary physical quantities associated with light waves: intensity, wavelength, directionality, and polarization. These are conventionally performed with a series of bulky optical elements, but recently, it has been recognized that optical resonances in nanostructures can be engineered to achieve selective photodetection of light waves with a specific set of predetermined properties. Here, we theoretically illustrate how a thin silicon layer can be patterned into a dislocated nanowire-array that affords detection of circularly polarized light with an efficiency that reaches the theoretical limit for circular dichroism of a planar detector in a symmetric external environment. The presence of a periodic arrangement of dislocations is essential in achieving such unparalleled performance as they enable selective excitation of nonlocal, guided-mode resonances for one handedness of light. We also experimentally demonstrate compact, high-performance chiral photodetectors created from these dislocated nanowire-arrays. This work highlights the critical role defects can play in enabling new nanophotonic functions and devices.
Anqi Ji; Jung-Hwan Song; Qitong Li; Fenghao Xu; Ching-Ting Tsai; Richard C Tiberio; Bianxiao Cui; Philippe Lalanne; Pieter G Kik; David AB Miller; Mark L Brongersma
Quantitative phase contrast imaging with a nonlocal angle-selective metasurface Journal Article
In: Nature Communications, vol. 13, iss. 1, pp. 1-7, 2022.
@article{ji2022quantitative,
title = {Quantitative phase contrast imaging with a nonlocal angle-selective metasurface},
author = {Anqi Ji and Jung-Hwan Song and Qitong Li and Fenghao Xu and Ching-Ting Tsai and Richard C Tiberio and Bianxiao Cui and Philippe Lalanne and Pieter G Kik and David AB Miller and Mark L Brongersma},
year = {2022},
date = {2022-12-21},
urldate = {2022-12-21},
journal = {Nature Communications},
volume = {13},
issue = {1},
pages = {1-7},
abstract = {Phase contrast microscopy has played a central role in the development of modern biology, geology, and nanotechnology. It can visualize the structure of translucent objects that remains hidden in regular optical microscopes. The optical layout of a phase contrast microscope is based on a 4 f image processing setup and has essentially remained unchanged since its invention by Zernike in the early 1930s. Here, we propose a conceptually new approach to phase contrast imaging that harnesses the non-local optical response of a guided-mode-resonator metasurface. We highlight its benefits and demonstrate the imaging of various phase objects, including biological cells, polymeric nanostructures, and transparent metasurfaces. Our results showcase that the addition of this non-local metasurface to a conventional microscope enables quantitative phase contrast imaging with a 0.02π phase accuracy. At a high level, this work adds to the growing body of research aimed at the use of metasurfaces for analog optical computing.},
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pubstate = {published},
tppubtype = {article}
}
Phase contrast microscopy has played a central role in the development of modern biology, geology, and nanotechnology. It can visualize the structure of translucent objects that remains hidden in regular optical microscopes. The optical layout of a phase contrast microscope is based on a 4 f image processing setup and has essentially remained unchanged since its invention by Zernike in the early 1930s. Here, we propose a conceptually new approach to phase contrast imaging that harnesses the non-local optical response of a guided-mode-resonator metasurface. We highlight its benefits and demonstrate the imaging of various phase objects, including biological cells, polymeric nanostructures, and transparent metasurfaces. Our results showcase that the addition of this non-local metasurface to a conventional microscope enables quantitative phase contrast imaging with a 0.02π phase accuracy. At a high level, this work adds to the growing body of research aimed at the use of metasurfaces for analog optical computing.
Qitong Li; Jorik van de Groep; Adam K. White; Jung-Hwan Song; Scott A. Longwell; Polly M. Fordyce; Stephen R. Quake; Pieter G. Kik; Mark L. Brongersma
Metasurface optofluidics for dynamic control of light fields Journal Article
In: Nature Nanotechnology, vol. 17, iss. 10, pp. 1097-1103, 2022.
@article{li2022metasurface,
title = {Metasurface optofluidics for dynamic control of light fields},
author = {Qitong Li and Jorik van de Groep and Adam K. White and Jung-Hwan Song and Scott A. Longwell and Polly M. Fordyce and Stephen R. Quake and Pieter G. Kik and Mark L. Brongersma},
doi = {10.1038/s41565-022-01197-y},
year = {2022},
date = {2022-09-26},
urldate = {2022-09-26},
journal = {Nature Nanotechnology},
volume = {17},
issue = {10},
pages = {1097-1103},
abstract = {The ability to manipulate light and liquids on integrated optofluidics chips has spurred a myriad of important developments in biology, medicine, chemistry and display technologies. Here we show how the convergence of optofluidics and metasurface optics can lead to conceptually new platforms for the dynamic control of light fields. We first demonstrate metasurface building blocks that display an extreme sensitivity in their scattering properties to their dielectric environment. These blocks are then used to create metasurface-based flat optics inside microfluidic channels where liquids with different refractive indices can be directed to manipulate their optical behaviour. We demonstrate the intensity and spectral tuning of metasurface colour pixels as well as on-demand optical elements. We finally demonstrate automated control in an integrated meta-optofluidic platform to open up new display functions. Combined with large-scale microfluidic integration, our dynamic-metasurface flat-optics platform could open up the possibility of dynamic display, imaging, holography and sensing applications.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The ability to manipulate light and liquids on integrated optofluidics chips has spurred a myriad of important developments in biology, medicine, chemistry and display technologies. Here we show how the convergence of optofluidics and metasurface optics can lead to conceptually new platforms for the dynamic control of light fields. We first demonstrate metasurface building blocks that display an extreme sensitivity in their scattering properties to their dielectric environment. These blocks are then used to create metasurface-based flat optics inside microfluidic channels where liquids with different refractive indices can be directed to manipulate their optical behaviour. We demonstrate the intensity and spectral tuning of metasurface colour pixels as well as on-demand optical elements. We finally demonstrate automated control in an integrated meta-optofluidic platform to open up new display functions. Combined with large-scale microfluidic integration, our dynamic-metasurface flat-optics platform could open up the possibility of dynamic display, imaging, holography and sensing applications.
Jung-Hwan Song; Søren Raza; Jorik van de Groep; Ju-Hyung Kang; Qitong Li; Pieter G. Kik; Mark L. Brongersma
Nanoelectromechanical modulation of a strongly-coupled plasmonic dimer Journal Article
In: Nature Communications, vol. 12, no. 48, 2021.
@article{song12nanoelectromechanical,
title = {Nanoelectromechanical modulation of a strongly-coupled plasmonic dimer},
author = {Jung-Hwan Song and S\oren Raza and Jorik van de Groep and Ju-Hyung Kang and Qitong Li and Pieter G. Kik and Mark L. Brongersma },
doi = {10.1038/s41467-020-20273-2},
year = {2021},
date = {2021-01-04},
journal = {Nature Communications},
volume = {12},
number = {48},
abstract = {The ability of two nearly-touching plasmonic nanoparticles to squeeze light into a nanometer gap has provided a myriad of fundamental insights into light\textendashmatter interaction. In this work, we construct a nanoelectromechanical system (NEMS) that capitalizes on the unique, singular behavior that arises at sub-nanometer particle-spacings to create an electro-optical modulator. Using in situ electron energy loss spectroscopy in a transmission electron microscope, we map the spectral and spatial changes in the plasmonic modes as they hybridize and evolve from a weak to a strong coupling regime. In the strongly-coupled regime, we observe a very large mechanical tunability (~250 meV/nm) of the bonding-dipole plasmon resonance of the dimer at ~1 nm gap spacing, right before detrimental quantum effects set in. We leverage our findings to realize a prototype NEMS light-intensity modulator operating at ~10 MHz and with a power consumption of only 4 fJ/bit.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The ability of two nearly-touching plasmonic nanoparticles to squeeze light into a nanometer gap has provided a myriad of fundamental insights into light–matter interaction. In this work, we construct a nanoelectromechanical system (NEMS) that capitalizes on the unique, singular behavior that arises at sub-nanometer particle-spacings to create an electro-optical modulator. Using in situ electron energy loss spectroscopy in a transmission electron microscope, we map the spectral and spatial changes in the plasmonic modes as they hybridize and evolve from a weak to a strong coupling regime. In the strongly-coupled regime, we observe a very large mechanical tunability (~250 meV/nm) of the bonding-dipole plasmon resonance of the dimer at ~1 nm gap spacing, right before detrimental quantum effects set in. We leverage our findings to realize a prototype NEMS light-intensity modulator operating at ~10 MHz and with a power consumption of only 4 fJ/bit.
Jorik van de Groep; Jung-Hwan Song; Umberto Celano; Qitong Li; Pieter G. Kik; Mark L. Brongersma
Exciton resonance tuning of an atomically thin lens Journal Article
In: Nature Photonics, vol. 14, pp. 426-430, 2020.
@article{van2020exciton,
title = {Exciton resonance tuning of an atomically thin lens},
author = {Jorik van de Groep and Jung-Hwan Song and Umberto Celano and Qitong Li and Pieter G. Kik and Mark L. Brongersma },
doi = {10.1038/s41566-020-0624-y},
year = {2020},
date = {2020-04-27},
journal = {Nature Photonics},
volume = {14},
pages = {426-430},
abstract = {The highly engineerable scattering properties of resonant optical antennas underpin the operation of metasurface-based flat optics. Thus far, the choice of antenna has been limited to shaped metallic and high-index semiconductor nanostructures that support geometrical plasmonic or Mie resonances. Whereas these resonant elements offer strong light\textendashmatter interaction and excellent control over the scattering phase and amplitude, their electrical tunability has proven to be quite limited. Here, we demonstrate how excitonic resonances in atomically thin semiconductors can be harnessed as a different, third type of resonance to create mutable, flat optics. These strong materials-based resonances are unmatched in their tunability with various external stimuli. To illustrate the concept, we first demonstrate how excitons can enhance the focusing efficiency of a millimetre-scale, patterned WS2 zone plate lens. We also show how electrical gating can completely turn on and off the exciton resonance and thereby modulate the focusing efficiency by 33%.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The highly engineerable scattering properties of resonant optical antennas underpin the operation of metasurface-based flat optics. Thus far, the choice of antenna has been limited to shaped metallic and high-index semiconductor nanostructures that support geometrical plasmonic or Mie resonances. Whereas these resonant elements offer strong light–matter interaction and excellent control over the scattering phase and amplitude, their electrical tunability has proven to be quite limited. Here, we demonstrate how excitonic resonances in atomically thin semiconductors can be harnessed as a different, third type of resonance to create mutable, flat optics. These strong materials-based resonances are unmatched in their tunability with various external stimuli. To illustrate the concept, we first demonstrate how excitons can enhance the focusing efficiency of a millimetre-scale, patterned WS2 zone plate lens. We also show how electrical gating can completely turn on and off the exciton resonance and thereby modulate the focusing efficiency by 33%.
