Xinchao Lu

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We experimentally demonstrate a chiral metamaterial exhibiting negative refractive index at terahertz frequencies. The presence of strong chirality in the terahertz metamaterial lifts the degeneracy for the two circularly polarized waves and allows for the achievement of negative refractive index without requiring simultaneously negative permittivity and(More)
We present resonant terahertz transmission in a composite plasmonic film comprised of an array of subwavelength metallic patches and semiconductor holes. A large dynamic transition between a dipolar localized surface plasmon mode and a surface plasmon resonance near 0.8 THz is observed under near infrared optical excitation. The reversal in transmission(More)
In the low-terahertz regime, the resonance frequency of an array of subwavelength holes in a semiconductor sheet can be doubled or more by isothermally increasing the magnitude of a dc magnetic field, by increasing the temperature in the presence of a constant dc magnetic field, and by increasing both the temperature and the dc magnetic field magnitude.
Controlling extraordinary transmission characteristics of metal hole arrays with spoof surface plasmons Appl. Study of plasmonic crystals using Fourier-plane images obtained with plasmon tomography far-field superlenses Tuning the wavelength drift between resonance light absorption and scattering of plasmonic nanoparticle Appl. Temperature dependence of(More)
Specific biorecognition is essential for many biological processes, for which highly sensitive and label-free biosensors are strongly demanded. The recently developed metamaterials are a potential choice for biosensing due to their exotic properties. In the current work, a label-free and specific sensor for streptavidin-agarose (SA) was fabricated based on(More)
We present a systematic numerical study of a metal-dielectric-metal sandwich plasmonic structure for broadband resonant transmission at terahertz frequencies. The proposed structure consists of periodic slotted metallic arrays on both sides of a thin dielectric substrate and is demonstrated to exhibit a broad passband transmission response. Various design(More)
Surface-enhanced electromagnetic response in the resonant regions of split-ring resonators offers a sensitive way to probe the surface dipoles formed by alkanethiol molecules with a terahertz wave by a differential transmission (DT) interrogation method. The DT signal mainly comes from the interaction between alkanethiols and metamaterials by electron(More)
We present a systematic study of a close-ring pair based freestanding metamaterial fabricated by double-layer, self-aligned photolithography. Terahertz time-domain spectroscopy transmission measurements and numerical simulations have revealed negative index of refraction in the frequency range of 0.66-0.90 THz under normal wave incidence. The observed(More)
Plasmonic structures made of periodically arranged metallic rings integrated into subwavelength holes are investigated at the far-infrared terahertz frequencies. The emergence and the interplay of various resonances sustained by such plasmonic samples are elucidated. To reveal a coherent physical picture, relevant dimensions of the samples are modified and(More)
We report on anomalous field enhancement of terahertz transmission in metallic, rectangular coaxial geometries. The integration of a particle in the hole not only results in a factor of eight increase in normalized transmittance compared to that of the hole-only counterpart, but it also tailors polarization-dependent transmission discrepancy encountered in(More)