A5058229517- Metamaterials and Metasurfaces Applications
- Thermal Radiation and Cooling Technologies
- Photonic Crystals and Applications
- Photonic and Optical Devices
- Plasmonic and Surface Plasmon Research
- Animal Behavior and Reproduction
- Neurobiology and Insect Physiology Research
- Insect and Arachnid Ecology and Behavior
- Plant and animal studies
- Organic Electronics and Photovoltaics
- Advanced Fiber Optic Sensors
- Molecular Junctions and Nanostructures
- Neural Networks and Reservoir Computing
- Urban Heat Island Mitigation
- Advanced Memory and Neural Computing
- Advanced Fluorescence Microscopy Techniques
- Advanced Antenna and Metasurface Technologies
- Fern and Epiphyte Biology
- Advanced Semiconductor Detectors and Materials
- Orbital Angular Momentum in Optics
- Remote Sensing in Agriculture
- Mechanical and Optical Resonators
- Topological Materials and Phenomena
- solar cell performance optimization
- Random lasers and scattering media
Columbia University
2015-2025
Apple (United States)
2024
Optica
2010
Keeping cool Silver ants inhabit one of the hottest and driest environments on Earth, Saharan sands, where most insects shrivel die moments after contact. Shi et al. show that triangular shape silver hairs cover their bodies enables this existence. The both increase reflection near-infrared rays dissipate heat from ants' bodies, even under full sun conditions. Evolution's simple solution to intense management in species could lead better designs for passive cooling human-produced objects....
Solar reflective and thermally emissive surfaces offer a sustainable way to cool objects under sunlight. However, white or silvery reflectance of these does not satisfy the need for color. Here, we present paintable bilayer coating that simultaneously achieves color radiative cooling. The comprises thin, visible-absorptive layer atop nonabsorptive, solar-scattering underlayer. top absorbs appropriate visible wavelengths show specific colors, while underlayer maximizes reflection...
Abstract Passive daytime radiative cooling (PDRC) can realize electricity‐free by reflecting sunlight and emitting heat to the cold space. Current PDRC designs often involve costly vacuum processing or a large quantity of harmful organic solvents. Aqueous paint‐like is cost‐effective environmentally benign, thereby highly attractive for green manufacturing coatings. However, common polymers explored in are difficult disperse water, let alone forming porous structures efficient cooling. Here,...
Broadband high reflectance in nature is often the result of randomly, three-dimensionally structured materials. This study explores unique optical properties associated with one-dimensional nanostructures discovered silk cocoon fibers comet moth, Argema mittrei. The are populated a density air voids randomly distributed across fiber cross-section but invariant along fiber. These filamentary strongly scatter light solar spectrum. A single measuring ~50 μm thick can reflect 66% incoming...
Abstract The wings of Lepidoptera contain a matrix living cells whose function requires appropriate temperatures. However, given their small thermal capacity, can overheat rapidly in the sun. Here we analyze butterfly across wide range simulated environmental conditions, and find that regions containing are maintained at cooler Diverse scale nanostructures non-uniform cuticle thicknesses create heterogeneous distribution radiative cooling selectively reduces temperature structures such as...
Abstract We synthesized crystalline films of neodymium nickel oxide (NdNiO 3 ), a perovskite quantum material, switched the from metal phase (intrinsic) into an insulator (electron-doped) by field-driven lithium-ion intercalation, and characterized their structural optical properties. Time-of-flight secondary-ion mass spectrometry (ToF-SIMS) showed that intercalation process resulted in gradient dopant concentration along thickness direction films, turning insulator–metal bilayers. used...
As ectotherms, insects need heat-sensitive receptors to monitor environmental temperatures and facilitate thermoregulation. We show that
Polymers have appealing optical, biochemical and mechanical qualities, including broadband transparency, ease of functionalization biocompatibility. However, their low refractive indices precluded wavelength-scale optical confinement nanophotonic applications in polymers. Here, we introduce a suspended polymer photonic crystal (SPPC) architecture that enables the implementation structures typically limited to high-index materials. Using SPPC platform, demonstrate band-edge filters,...
We present an economical imaging system with integrated hardware and software to capture multispectral images of Lepidoptera high efficiency. This method facilitates the comparison colors shapes among species at fine broad taxonomic scales may be adapted for other insect orders greater three-dimensionality. Our can image both dorsal ventral sides pinned specimens. Together our processing pipeline, descriptive data used systematically investigate based on full-wing reconstruction a...
ABSTRACT The Australian lycaenid butterfly Jalmenus evagoras has iridescent wings that are sexually dimorphic, spectrally and in their degree of polarization, suggesting these properties likely to be important mate recognition. We first describe the results a field experiment showing free-flying individuals J. discriminate between visual stimuli vary polarization content blue wavelengths but not others. then present detailed reflectance spectrophotometry measurements male female wings,...
Abstract Dynamic wavefront shaping with optical metasurfaces has presented a major challenge and inspired large number of highly elaborate solutions. Here, this study experimentally demonstrates thermo‐optically reconfigurable, nonlocal using simple device architectures conventional CMOS‐compatible dielectric materials. These support quasi‐bound states in the continuum (q‐BICs) derived from symmetry breaking encoded spatially varying geometric phase, such that they shape exclusively on...
We demonstrate that optical ring resonators can be used as time-resolved refractive index sensors embedded in microfluidic channels. The nanophotonic structures are integrated into soft silicone microchannels interfaced with a transparent hard polymer manifold and standard connections. steady-state sensitivity, resolution detection limit of the characterized using aqueous saline solutions at various concentrations. Time-resolved measurements performed by sensing thin liquid films (0–400 nm)...
We present a general approach for coupling specific mode in planar photonic crystal (PC) waveguide to desired free-space mode. apply this W1 PC by introducing small index perturbations selectively couple particular transverse an approximately Gaussian, slowly diverging free space This "perturbative coupler" (PPCWC) enables efficient interconversion between selectable propagating and modes with minimal design perturbations.
We discovered that the spatial distribution of coloration and emissivity butterfly wings help regulate wing temperatures, variation thermal is mainly controlled by nano-structures scales.
The study shows that comet moth cocoon fibers exhibit radiative cooling properties with enhanced solar reflectivity and thermal emissivity. Optical waveguiding due to transverse Anderson localization of light is also observed in these natural fibers.
The study shows how Saharan silver ants utilize a uniquely shaped hair coating to substantially enhance reflectivity in the solar spectrum and emissivity mid-infrared. Biomimetic metasurfaces with such radiative-cooling properties are also reported.
We fabricated GaN metasurfaces doped with InGaN quantum dots by templated molecular beam epitaxy (MBE) that support tunable high Q-factor quasi-bound states in the continuum (q-BICs) and demonstrated efficient optical nonlinear conversion using this platform.
We synthesized crystalline films of neodymium nickel oxide (NdNiO3), a perovskite quantum material, switched the from metal phase (intrinsic) into an insulator (electron-doped) by field-driven lithium-ion intercalation, and characterized their structural optical properties. Time-of-flight secondary-ion mass spectrometry (ToF-SIMS) showed that intercalation process resulted in gradient dopant concentration along thickness direction films, turning insulator-metal bilayers. used variable-angle...
Summary Identifying the genes and mutations that drive phenotypic variation which are subject to selection is crucial for understanding evolutionary processes. Mormon Fritillary butterflies ( Speyeria mormonia ) exhibit a striking wing color polymorphism throughout their range: typical morphs bear silver spots on ventral surfaces, can co-occur with unsilvered displaying dull coloration 1 . Through genome-wide association studies in two polymorphic populations, we fine-map this difference...
We describe a general method for maximizing the short-circuit current in thin planar organic photovoltaic (OPV) heterojunction cells by simultaneous optimization of light absorption and carrier collection. Based on experimentally obtained complex refractive indices OPV materials thickness-dependence internal quantum efficiency active layer, we analyze potential benefits trapping strategies overall power conversion cell. This approach provides strategy optimizing wide range structures. In...
We describe surface patterning strategies that permit high photon-collection efficiency together with carrier-collection in an ultra-thin planar heterojunction organic photovoltaic cell. Optimized designs reach up to 50% photon collection a P3HT layer of only 30 nm, representing 3- 5-fold improvement over unpatterned cell the same thickness. compare enhancement light confinement active ITO top for TE and TM polarized light, demonstrate absorption can increase by factor 2 due gap-plasmon mode layer.
We demonstrate a novel approach to realize optical neural networks by condensing the layered computations into singlet of metasurface device which provides task-specific transformations signals for recognizing identity an object.