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We propose an active plasmonic device based on graphene. Highly confined plasmonic waves in monolayer graphene are efficiently excited using an etched diffractive grating on silicon. The guided-wave resonance of the combined structure creates a sharp notch on the normal-incidence transmission spectra, as the incident optical wave couples to the graphene(More)
We experimentally demonstrate feedback controlling of the resonant wavelength of a silicon dual-ring resonator. The feedback signal is the difference in optical scattering from the two coupled microring resonators, and the control mechanism is based on thermo-optic tuning with micro-heaters. This control scheme keeps the central wavelength of the resonator(More)
In this Letter we fabricate and characterize suspended silicon (Si) waveguides and ring resonators for mid-infrared wavelength range. Both tunable laser and thermal tuning are used to cover wavelength ranges near 5.2 and 3.4 μm. The loaded quality factors are estimated at 2700 at 5.2 μm and 7900 at 3.4 μm. Heat induced spectrum distortion is observed.(More)
We have detected trace amounts of molecules of antibiotics (kanamycin sulfate) dispersed on metasurfaces with terahertz (THz) spectroscopy. Utilizing the extraordinary optical transmission resonance of an array of square-shaped slits on a silicon substrate at ~0.3 THz, we were able to monitor varying concentrations of kanamycin sulfate as low as ~100(More)
We demonstrate the excitation and gate control of highly confined surface plasmon polaritons propagating through monolayer graphene using a silicon diffractive grating. The normal-incidence infrared transmission spectra exhibit pronounced dips due to guided-wave resonances, whose frequencies can be tuned over a range of ~80 cm(-1) by applying a gate(More)
Gate-controllable transmission of terahertz (THz) radiation makes graphene a promising material for making high-speed THz wave modulators. However, to date, graphene-based THz modulators have exhibited only small on/off ratios due to small THz absorption in single-layer graphene. Here we demonstrate a ∼50% amplitude modulation of THz waves with gated(More)
The field lines of the Poynting vector for light emitted by a dipole with a rotating dipole moment show a vortex pattern near the location of the dipole. In the far field, each field line approaches a straight line, but this line does not appear to come exactly from the location of the dipole. As a result, the image of the dipole in its plane of rotation(More)
We demonstrated extraordinary THz transmission through ring apertures on a metal film. Transmission of 60% was obtained with an aperture-to-area ratio of only 1.4%. We show that the high transmission can be suppressed by over 18 dB with a thin layer of free carriers in the silicon substrate underneath the metal film. This result suggests that(More)
We propose an efficient optical coupler between a submicrometer-sized silicon waveguide on a silicon photonic chip and a multi-micrometer wide polymer waveguide on an optical printed circuit board for interchip optical networks. We show low coupling loss <0.4 dB with high lateral and angular tolerance to misalignment so that coupling can be done by(More)
We have fabricated a novel nanoweb fiber with web-like bundle of the fused-silica membranes with different thickness in its cross section. We pumped the 0.55-μm-thick membrane with 200-fs laser pulse at 800-nm just adjacent to its second-zero-dispersion wavelength, and demonstrated the polarization dependent visible supercontinuum (SC). The mode patterns(More)