253 citations · 556 across the 20 of their papers we have counts for
21 papers
Giant Modulation of Refractive Index from Picoscale Atomic Displacements
Boyang Zhao, Guodong Ren, Hongyan Mei +21
Structural disorder has been shown to enhance and modulate magnetic, electrical, dipolar, electrochemical, and mechanical properties of materials. However, the possibility of obtai…
Colossal optical anisotropy from atomic-scale modulations
Hongyan Mei, Guodong Ren, Boyang Zhao +17
In modern optics, materials with large birefringence (Δn, where n is the refractive index) are sought after for polarization control (e.g. in wave plates, polarizing beam splitters…
Heavily doped zinc oxide with plasma frequencies in the telecommunication wavelength range
Alexander Koch, Hongyan Mei, Jura Rensberg +10
We demonstrate heavy and hyper doping of ZnO by a combination of gallium (Ga) ion implantation using a focused ion beam (FIB) system and post-implantation laser annealing. Ion impl…
Tuning carrier density and phase transitions in oxide semiconductors using focused ion beams
Hongyan Mei, Alexander Koch, Chenghao Wan +10
We demonstrate spatial modification of the optical properties of thin-film metal oxides, zinc oxide and vanadium dioxide as representatives, using a commercial focused ion beam (FI…
Switchable induced-transmission filters enabled by vanadium dioxide
Chenghao Wan, David Woolf, Colin M. Hessel +6
Abstract: An induced-transmission filter (ITF) uses an ultrathin layer of metal positioned at an electric-field node within a dielectric thin-film bandpass filter to select one tra…
Passive frequency conversion of ultraviolet images into the visible using perovskite nanocrystals
Jad Salman, Mahesh K. Gangishetty, Bryan E. Rubio-Perez +8
We demonstrate a passive down-conversion imaging system that converts broadband ultraviolet light to narrow-band green light while preserving the directionality of rays, and thus e…
Planck spectroscopy
Yuzhe Xiao, Chenghao Wan, Jad Salman +4
All spectrometers rely on some mechanism to achieve spectral selectivity; common examples include gratings, prisms, and interferometers with moving mirrors. We experimentally demon…
Hyperspectral interference tomography of nacre
Jad Salman, Cayla A. Stifler, Alireza Shahsafi +12
Structural characterization of biologically formed materials is essential for understanding biological phenomena and their environment, and generating new bio-inspired engineering…
Infrared polarizer based on direct coupling to surface-plasmon polaritons
A. Shahsafi, J. Salman, B. E. Rubio Perez +3
We propose a new type of reflective polarizer based on polarization-dependent coupling to surface-plasmon polaritons (SPPs) from free space. This inexpensive polarizer is relativel…
Ultrathin broadband reflective optical limiter
Chenghao Wan, Zhen Zhang, Jad Salman +7
Optical limiters are nonlinear devices that feature decreasing transmittance with increasing incident optical intensity, and thus can protect sensitive components from high-intensi…
Guidelines for measurement of thermal emission
Yuzhe Xiao, Chenghao Wan, Alireza Shahsafi +7
Thermal emission is the radiation of electromagnetic waves from hot objects. The promise of thermal-emission engineering for applications in energy harvesting, radiative cooling, a…
Depth thermography: non-invasive 3D temperature profiling using infrared thermal emission
Yuzhe Xiao, Chenghao Wan, Alireza Shahsafi +2
We introduce a technique based on infrared thermal emission, termed depth thermography, that can remotely measure the temperature distribution beneath the surface of certain object…
Wide-angle spectrally selective absorbers and thermal emitters based on inverse opals
Alireza Shahsafi, Graham Joe, Soeren Brandt +8
Engineered optical absorbers are of substantial interest for applications ranging from stray light reduction to energy conversion. We demonstrate a large-area (centimeter-scale) me…
Temperature-independent thermal radiation
Alireza Shahsafi, Patrick Roney, You Zhou +11
Thermal emission is the process by which all objects at non-zero temperatures emit light, and is well-described by the classic Planck, Kirchhoff, and Stefan-Boltzmann laws. For mos…
Optical properties of thin-film vanadium dioxide from the visible to the far infrared
Chenghao Wan, Zhen Zhang, David Woolf +13
The insulator-to-metal transition (IMT) in vanadium dioxide (VO2) can enable a variety of optics applications, including switching and modulation, optical limiting, and tuning of o…
Nanosecond mid-infrared pulse generation via modulated thermal emissivity
Yuzhe Xiao, Nicholas A. Charipar, Jad Salman +2
We demonstrate the generation of nanosecond mid-infrared pulses via fast modulation of thermal emissivity, enabled by the absorption of visible pump pulses in unpatterned silicon a…
Multi-refractive-index metamaterials based on subwavelength waveguide arrays
Zhaoning Yu, Chenghao Wan, Jad Salman +4
We demonstrate a metamaterial that cannot be described by a single set of refractive-index and impedance values, even for fixed frequency and polarization. The metamaterial structu…
Thermal-emission measurements near room temperature using Fourier-transform infrared spectroscopy
Yuzhe Xiao, Alireza Shahsafi, Chenghao Wan +5
Accurate characterization of thermal emitters can be challenging due to the presence of background thermal emission from components of the experimental setup and the surrounding en…
Mid-infrared optics using dielectrics with refractive indices below unity
Alireza Shahsafi, Yuzhe Xiao, Jad Salman +4
Conventional transparent materials at optical frequencies have refractive index values (n) greater than unity -- most commonly between about 1 and 4. This paper explores optical ph…
Limiting optical diodes enabled by the phase transition of vanadium dioxide
Chenghao Wan, Erik Horak, Jonathan King +8
A limiting optical diode is an asymmetric nonlinear device that is bidirectionally transparent at low power, but becomes opaque when illuminated by sufficiently intense light incid…
Enhancing human color vision by breaking binocular redundancy
Bradley S. Gundlach, Michel Frising, Alireza Shahsafi +6
To see color, the human visual system combines the response of three types of cone cells in the retina--a compressive process that discards a significant amount of spectral informa…