A5081440129- Metamaterials and Metasurfaces Applications
- Advanced Antenna and Metasurface Technologies
- Orbital Angular Momentum in Optics
- Plasmonic and Surface Plasmon Research
- Photonic and Optical Devices
- Antenna Design and Analysis
- Photonic Crystals and Applications
- Optical Coatings and Gratings
- Advanced Optical Imaging Technologies
- Optical Wireless Communication Technologies
- Polydiacetylene-based materials and applications
- Microwave Engineering and Waveguides
- Random lasers and scattering media
- Advanced Fiber Optic Sensors
- Advanced Materials and Mechanics
- Radio Wave Propagation Studies
- Superconducting and THz Device Technology
- Near-Field Optical Microscopy
- Photoreceptor and optogenetics research
- Digital Holography and Microscopy
- Semiconductor Lasers and Optical Devices
- Antenna Design and Optimization
- Underwater Vehicles and Communication Systems
- Advanced Fiber Laser Technologies
- Electromagnetic Compatibility and Measurements
California Institute of Technology
2015-2020
Kavli Energy NanoScience Institute
2019
Samsung (United States)
2017
University of Tehran
2013-2016
University of Illinois Urbana-Champaign
2014-2015
Sharif University of Technology
2005
Varifocal lenses, conventionally implemented by changing the axial distance between multiple optical elements, have a wide range of applications in imaging and beam scanning. The use conventional bulky refractive elements makes these varifocal lenses large, slow, limits their tunability. Metasurfaces, new category lithographically defined diffractive devices, enable thin lightweight with precisely engineered phase profiles. Here, we demonstrate tunable metasurface doublets, based on...
Abstract Optical metasurfaces are two-dimensional arrays of nano-scatterers that modify optical wavefronts at subwavelength spatial resolution. They poised to revolutionize optics by enabling complex low-cost systems where multiple lithographically stacked and integrated with electronics. For imaging applications, metasurface stacks can perform sophisticated image corrections be directly sensors. Here we demonstrate this concept a miniature flat camera integrating monolithic lens doublet...
Metasurfaces are nano-structured devices composed of arrays subwavelength scatterers (or meta-atoms) that manipulate the wavefront, polarization, or intensity light. Like other diffractive optical devices, metasurfaces suffer from significant chromatic aberrations limit their bandwidth. Here, we present a method for designing multiwavelength using unit cells with multiple meta-atoms, meta-molecules. Transmissive lenses efficiencies as high 72% and numerical apertures 0.46 simultaneously...
Abstract Dielectric metasurfaces are two‐dimensional structures composed of nano‐scatterers that manipulate the phase and polarization optical waves with subwavelength spatial resolution, thus enabling ultra‐thin components for free‐space optics. While high performance devices various functionalities, including some difficult to achieve using conventional setups have been shown, most demonstrated fixed parameters. Here, we demonstrate highly tunable dielectric metasurface based on thick...
Polarization is a degree of freedom light carrying important information that usually absent in intensity and spectral content. Imaging polarimetry the process determining polarization state light, either partially or fully, over an extended scene. It has found several applications various fields, from remote sensing to biology. Among different devices for imaging polarimetry, division focal plane cameras (DoFP-PCs) are more compact, less complicated, expensive. In general, DoFP-PCs based on...
Abstract Physical geometry and optical properties of objects are correlated: cylinders focus light to a line, spheres point arbitrarily shaped introduce aberrations. Multi-functional components with decoupled geometrical form function needed when specific functionalities must be provided while the shapes dictated by other considerations like ergonomics, aerodynamics or aesthetics. Here we demonstrate an approach for decoupling from their physical shape using thin flexible dielectric...
The angular response of thin diffractive optical elements is highly correlated. For example, the angles incidence and diffraction a grating are locked through momentum determined by period. Other devices, including conventional metasurfaces, have similar behavior due to fixed locations Fresnel zone boundaries weak sensitivity meta-atoms. To alter this fundamental property, we introduce angle-multiplexed composed reflective high-contrast dielectric U-shaped meta-atoms, whose under...
Abstract To increase system capacity of underwater optical communications, we employ the spatial domain to simultaneously transmit multiple orthogonal beams, each carrying an independent data channel. In this paper, show up a 40-Gbit/s link by multiplexing and transmitting four green orbital angular momentum (OAM) beams through single aperture. Moreover, investigate degrading effects scattering/turbidity, water current, thermal gradient-induced turbulence, find that gradients cause most...
Abstract Metasurfaces are two-dimensional arrangements of optical scatterers rationally arranged to control wavefronts. Despite the significant advances made in wavefront engineering through metasurfaces, most these devices designed for and operate at a single wavelength. Here we show that spatial multiplexing schemes can be applied increase number operation wavelengths. We use high contrast dielectric transmittarray platform with amorphous silicon nano-posts demonstrate polarization...
Optical metasurfaces are two-dimensional arrays of meta-atoms that modify different characteristics light such as phase, amplitude, and polarization. One intriguing feature distinguishes them from conventional optical components is their multifunctional capability. However, with efficiencies approaching those single-functional counterparts require more degrees freedom. Here we show 2.5D metastructures, which stacked layers interacting metasurface layers, provide sufficient freedom to...
An optical design space that can highly benefit from the recent developments in metasurfaces is folded optics architecture where light confined between reflective surfaces, and wavefront controlled at interfaces. In this manuscript, we introduce concept of metasurface by demonstrating a compact spectrometer made 1-mm-thick glass slab with volume 7 cubic millimeters. The has resolution ~1.2 nm, resolving more than 80 spectral points 760 to 860 nm. device composed three dielectric...
We report transmissive color filters based on subwavelength dielectric gratings that can replace conventional dye-based used in backside-illuminated CMOS image sensor (BSI CIS) technologies. The are patterned an 80 nm-thick poly silicon film a 115 SiO2 spacer layer. They optimized for operating at the primary RGB colors, exhibit peak transmittance of 60-80%, and have almost insensitive response over ± 20° angular range. This technology enables shrinking pixel sizes down to near micrometer.
Controlling the polarization of light has been interest for various applications in laser materials processing, display systems, and spectroscopy among others. Despite great advancements, level control over using naturally birefringent liquid crystals is still limited. In recent years, dielectric metasurfaces have enabled an unprecedented phase light. Here, we demonstrate vectorial holograms with almost arbitrary patterns structurally metasurfaces. Using a modified Gerchberg-Saxton algorithm...
Two-photon microscopy is a key imaging technique in life sciences due to its superior deep-tissue capabilities. Light-weight and compact two-photon microscopes are of great interest because their applications for vivo deep brain imaging. Recently, dielectric metasurfaces have enabled new category small lightweight optical elements, including objective lenses. Here we experimentally demonstrate using double-wavelength metasurface lens. It specifically designed focus 820 605 nm light,...
Hyperspectral imaging is a key characterization technique used in various areas of science and technology. Almost all implementations hyperspectral imagers rely on bulky optics including spectral filters moving or tunable elements. Here, we propose demonstrate line-scanning folded metasurface imager (HSI) that fabricated single lithographic step 1 mm thick glass substrate. The HSI composed four metasurfaces, three reflective one transmissive, are designed to collectively disperse focus light...
Spatiotemporal control of optical wavefronts is great importance in numerous free-space applications including imaging 3D and through scattering media, remote sensing, generation various beam profiles for microscopy. Progress these currently limited due to lack compact high-speed spatial light modulators. Here we report an active antenna comprising a coupled asymmetric Fabry–Perot resonator that produces phase-dominant thermo-optic modulation reflected at frequencies approaching tens...
Abstract One of the important advantages optical metasurfaces over conventional diffractive elements is their capability to efficiently deflect light by large angles. However, are conventionally designed using approaches that optimal for small deflection angles and performance designing high numerical aperture devices not well quantified. Here we introduce apply a technique estimation efficiency metasurfaces. The based on particular coherent averaging diffraction coefficients periodic blazed...
Various speckle-based computational imaging techniques that exploit the ability of scattering media to transfer hidden information into speckle pattern have recently been demonstrated.Current implementations suffer from several drawbacks associated with use conventional (CSM), such as their time-consuming characterization, instability time, and limited memory-effect range.Here we show by using a random dielectric metasurface diffuser (MD) known properties, many these issues can be...
Microring and microdisk lasers are potential candidates for small footprint, low threshold in-plane integrated lasers; however, they exhibit multimode lasing spectra bistability. Here, we theoretically propose experimentally demonstrate a novel approach achieving single mode in microring lasers. Our is based on increasing the radiation loss of all but one resonant modes resonators by integrating second order gratings microrings' waveguide. We present operation electrically pumped...
We demonstrate a self-rolled-up microtube-based vertical photonic coupler monolithically integrated on top of ridge waveguide to achieve three-dimensional (3D) integration. The fabrication process is fully compatible with standard planar silicon processing technology. Strong light coupling between the and was observed experimentally, which may provide an alternative route for 3D heterogeneous highest extinction ratio in transmission spectrum passing through 23 dB.
Significance Fast submicrometer-scale 3D printing techniques are of interest for various applications ranging from photonics and electronics to tissue engineering. Interference lithography is a versatile method with the ability generate complicated nanoscale structures. Its application, however, has been hindered by either setups in multibeam that cause sensitivity impede scalability or limited level control over fabricated structure achievable mask-assisted processes. Here, we show...