- Fundamental Limitations of Huygens' Metasurfaces for Optical Beam Shaping LASER & PHOTONICS REVIEWS 2021
- Structural color from a coupled nanowire pair beyond the bonding and antibonding model OPTICA 2021; 8 (4): 464-470
Nanoelectromechanical modulation of a strongly-coupled plasmonic dimer.
2021; 12 (1): 48
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 (~250meV/nm) of the bonding-dipole plasmon resonance of the dimer at ~1nm gap spacing, right before detrimental quantum effects set in. We leverage our findings to realize a prototype NEMS light-intensity modulator operating at ~10MHz and with a power consumption of only 4 fJ/bit.
View details for DOI 10.1038/s41467-020-20273-2
View details for PubMedID 33397929
- Exciton resonance tuning of an atomically thin lens NATURE PHOTONICS 2020
Transparent multispectral photodetectors mimicking the human visual system.
2019; 10 (1): 4982
Compact and lightweight photodetection elements play a critical role in the newly emerging augmented reality, wearable and sensing technologies. In these technologies, devices are preferred to be transparent to form an optical interface between a viewer and the outside world. For this reason, it is of great value to create detection platforms that are imperceptible to the human eye directly onto transparent substrates. Semiconductor nanowires (NWs) make ideal photodetectors as their optical resonances enable parsing of the multi-dimensional information carried by light. Unfortunately, these optical resonances also give rise to strong, undesired light scattering. In this work, we illustrate how a new optical resonance arising from the radiative coupling between arrayed silicon NWs can be harnessed to remove reflections from dielectric interfaces while affording spectro-polarimetric detection. The demonstrated transparent photodetector concept opens up promising platforms for transparent substrates as the base for opto-electronic devices and in situoptical measurement systems.
View details for DOI 10.1038/s41467-019-12899-8
View details for PubMedID 31676782
- Spin-Switched Three-Dimensional Full-Color Scenes Based on a Dielectric Meta-hologram ACS PHOTONICS 2019; 6 (11): 2910–16
Reversible and selective ion intercalation through the top surface of few-layer MoS2.
2018; 9 (1): 5289
Electrochemical intercalation of ions into the van der Waals gap of two-dimensional (2D) layered materials is a promising low-temperature synthesis strategy to tune their physical and chemical properties. It is widely believed that ions prefer intercalation into the van der Waals gap through the edges of the 2D flake, which generally causes wrinkling and distortion. Here we demonstrate that the ions can also intercalate through the top surface of few-layer MoS2 and this type of intercalation is more reversible and stable compared to the intercalation through the edges. Density functional theory calculations show that this intercalation is enabled by the existence of natural defects in exfoliated MoS2 flakes. Furthermore, we reveal that sealed-edge MoS2 allows intercalation of small alkali metal ions (e.g., Li+ and Na+) and rejects large ions (e.g., K+). These findings imply potential applications in developing functional 2D-material-based devices with high tunability and ion selectivity.
View details for PubMedID 30538249
- Order and Disorder Embedded in a Spectrally Interleaved Metasurface ACS PHOTONICS 2018; 5 (12): 4764–68
Spectrally interleaved topologies using geometric phase metasurfaces
2018; 26 (23): 31031–38
Metasurfaces facilitate the interleaving of multiple topologies in an ultra-thin photonic system. Here, we report on the spectral interleaving of topological states of light using a geometric phase metasurface. We realize that a dielectric spectrally interleaved metasurface generates multiple interleaved vortex beams at different wavelengths. By harnessing the space-variant polarization manipulations that are enabled by the geometric phase mechanism, a vectorial vortex array is implemented. The presented interleaved topologies concept can greatly enhance the functionality of advanced microscopy and communication systems.
View details for DOI 10.1364/OE.26.031031
View details for Web of Science ID 000449972600116
View details for PubMedID 30469990