Scholars@Duke
Willie John Padilla

Featured Works

Broadband and ultrahigh optical haze thin films with self-aggregated alumina nanowire bundles for photovoltaic applications

Journal article Energy and Environmental Science · September 1, 2015 Featured Work Optical haze is one of the most important factors to be considered in the development of efficient photonic and optoelectronic devices by manipulating the light behavior. In this work, we fabricated a high optical haze film composed of self-aggregated alum ... Full text Cite

Bi-layer metamaterials as fully functional near-perfect infrared absorbers

Journal article Applied Physics Letters · July 13, 2015 Featured Work In this letter, we discuss the design, fabrication, and experimental characterization of a bi-layer fully functional near-perfect metamaterial absorber (MMA) in the long-wavelength infrared (LWIR), which is broadband and generally insensitive to polarizati ... Full text Open Access Cite

Dynamic electromagnetic metamaterials

Journal article Materials Today · January 1, 2015 Featured Work Electromagnetic metamaterials are designer materials made from 'artificial atoms' which provide unprecedented control over light matter interactions. Metamaterials are fashioned to yield a specific response to the electric and magnetic components of light ... Full text Cite

Post-processing approach for tuning multi-layered metamaterials

Journal article Applied Physics Letters · October 13, 2014 Featured Work We propose a post-processing approach to efficiently tune the resonance frequency in double-layered terahertz metamaterials separated by a bonding agent. By heating the bonding agent, it is possible to move one metamaterial layer laterally with respect to ... Full text Cite

Plasmonic Resonance toward Terahertz Perfect Absorbers

Journal article ACS Photonics · July 16, 2014 Featured Work Metamaterial perfect absorbers have garnered significant interest with applications in sensing, imaging, and energy harnessing. Of particular interest are terahertz absorbers to overcome the weak terahertz response of natural materials. Here, we propose lo ... Full text Cite

Stable high temperature metamaterial emitters for thermophotovoltaic applications

Journal article Applied Physics Letters · May 19, 2014 Featured Work We report a metamaterial design for a thermophotovoltaic (TPV) emitter. TPVs are similar to photovoltaic solar cells, but they convert heat to electricity instead of sunlight. The focus of this paper is on the emitter stage of the TPV system, which convert ... Full text Cite

Liquid crystal metamaterial absorber spatial light modulator for THz applications

Journal article Advanced Optical Materials · March 1, 2014 Featured Work A terahertz (THz) spatial light modulator implemented with metamaterial absorbers (MMAs) functionalized with isothiocyanate-based liquid crystals (LCs) is experimentally demonstrated. The device is designed to work in reflection mode and is arranged in a 6 ... Full text Cite

Coded and compressive THz imaging with metamaterials

Journal article Proceedings of SPIE the International Society for Optical Engineering · January 1, 2014 Featured Work Imaging in long wavelength regimes holds huge potential in many fields, from security to skin cancer detection. However, it is often difficult to image at these frequencies - the so called 'THz gap1' is no exception. Current techniques generally ... Full text Cite

Terahertz compressive imaging with metamaterial spatial light modulators

Journal article Nature Photonics · 2014 Featured Work Cite

Terahertz compressive imaging with metamaterial spatial light modulators

Journal article Nature Photonics · January 1, 2014 Featured Work Imaging at long wavelengths, for example at terahertz and millimetre-wave frequencies, is a highly sought-after goal of researchers because of the great potential for applications ranging from security screening and skin cancer detection to all-weather nav ... Full text Cite

Interferometric direction finding with a metamaterial detector

Journal article Applied Physics Letters · December 16, 2013 Featured Work We present measurements and analysis demonstrating useful direction finding of sources in the S band (2-4 GHz) using a metamaterial detector. An augmented metamaterial absorber that supports magnitude and phase measurement of the incident electric field, w ... Full text Cite

Four-color metamaterial absorber THz spatial light modulator

Journal article Advanced Optical Materials · December 1, 2013 Featured Work Full text Cite

Spin-induced optical conductivity in the spin-liquid candidate herbertsmithite.

Journal article Physical review letters · September 2013 Featured Work We report a direct measurement of the low-frequency optical conductivity of large-area single-crystal herbertsmithite, a promising spin-liquid candidate material, by means of terahertz time-domain spectroscopy. In the spectral range below 1.4 THz, we obser ... Full text Cite

Dynamic Manipulation of Infrared Radiation with MEMS Metamaterials

Journal article Advanced Optical Materials · August 1, 2013 Featured Work An electrically tunable MEMS metamaterial that effectively manipulates radiation in the mid-infrared wavelength range is experimentally demonstrated. The metamaterial consists of an array of suspended metal-dielectric elements above a metal ground plane on ... Full text Cite

Metamaterial-based imaging for potential security applications

Conference Proceedings of SPIE the International Society for Optical Engineering · June 3, 2013 Featured Work In this paper, we present two different types of THz spatial light modulators (SLMs) that use dynamic metamaterials (MMs) to enable multiplex imaging. One imaging setup consists of a doped semiconducting MM as the SLM, with multi-color super-pixels compose ... Full text Cite

Terahertz single pixel imaging with an optically controlled dynamic spatial light modulator.

Journal article Optics express · May 2013 Featured Work We present a single pixel terahertz (THz) imaging technique using optical photoexcitation of semiconductors to dynamically and spatially control the electromagnetic properties of a semiconductor mask to collectively form a THz spatial light modulator (SLM) ... Full text Cite

Broadband light-trapping enhancement in an ultrathin film a-Si absorber using whispering gallery modes and guided wave modes with dielectric surface-textured structures.

Journal article Advanced materials (Deerfield Beach, Fla.) · May 2013 Featured Work An embedded nanosphere dielectric structure on an a-Si ultrathin film improves weighted absorption from 23.8% to 39.9%. The PMMA embedding layer offers a guided wave mode as well as mechanical robustness, in addition to the resonant whispering gallery mode ... Full text Cite

Liquid crystal tunable metamaterial absorber.

Journal article Physical review letters · April 2013 Featured Work We present an experimental demonstration of electronically tunable metamaterial absorbers in the terahertz regime. By incorporation of active liquid crystal into strategic locations within the metamaterial unit cell, we are able to modify the absorption by ... Full text Cite

A Subwavelength Extraordinary-Optical-Transmission Channel in Babinet Metamaterials

Journal article Advanced Optical Materials · March 1, 2013 Featured Work Babinet metamaterials exhibit higher transmission efficiencies at lower frequencies than traditional extraordinary-optical-transmission designs and provide an additional parameter for the creation of more efficient aperture structures, which may be useful ... Full text Cite

Optical Transmission: A Subwavelength Extraordinary-Optical-Transmission Channel in Babinet Metamaterials (Advanced Optical Materials 3/2013)

Journal article Advanced Optical Materials · March 1, 2013 Featured Work W. J. Padilla and co-workers report on page 221 extremely subwavelength extraordinary optical transmission (EOT) using Babinet metamaterial apertures. The front cover image depicts enhanced transmission and the importance of the strong coupling between lig ... Full text Cite