The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
We describe experimental measurements and simulations of a switchable THz metasurface device in a slab waveguide geometry. The device exhibits giant phase modulation of the TE1 mode at particular frequencies determined by the metamaterial geometry. Simulations predict that a 2π phase shift can be realized in an interaction length of only a few millimeters.
Metamaterials and metasurfaces have demonstrated many unusual properties that are useful for creating high-performance terahertz devices and components. Integration of functional materials allows metasurfaces to expand their scope of applications. Here we show that hybrid metasurfaces can provide ultrafast modulation of terahertz waves that are critical for future applications in terahertz imaging...
We present an electrically modulated nonlinear metamaterial at terahertz frequencies. The device consists of a planar array of split-ring resonators (SRRs) fabricated on n-type GaAs. Increasing the incident THz field strength induces carriers in the GaAs substrate, shorting the SRR capacitive gap and modulating the MM resonance. The application of a 15V bias to the MM reduces the net field modulation...
We describe experimental characterization of switchable THz metasurfaces using variable-angle broadband THz ellipsometry. A theoretical framework is used to extract surface susceptibility tensors as a function of frequency and applied DC bias. This will allow us to make a priori predictions of the performance of these devices for applications as metasurface active components.
We experimentally and numerically investigate a switchable dielectric-slab-waveguide metasurface device. We use an active metasurface to manipulate the interaction with a propagating THz surface wave, giving us dynamic control of the wave at 0.3 THz.
We design and test a switchable diffraction grating based on active metamaterials for terahertz modulation. We observe off-axis diffraction which permits operation of the device as a high-contrast modulator, with better than 20 dB of dynamic range.
We design and test a switchable diffraction grating based on active metamaterials for terahertz modulation. We observe off-axis diffraction which permits operation of the device as a narrowband high-contrast modulator.
The interrelation between transmission amplitude and phase spectra of anisotropic metamaterials enables us to develop realistic designs for a terahertz quarter-wave plate and a polarizing terahertz beam splitter based on an anisotropic metamaterial structure.
We have designed, fabricated and measured a first generation external modulator for a ~2.4 terahertz quantum cascade laser based on an electrically-driven active terahertz metamaterial structure.
In this work, we demonstrate THz metamaterials exhibiting either amplitude control, via carrier injection or depletion in the active semiconductor substrate or frequency control, via photoexcitation of carriers into active semiconducting materials incorporated into the sub-wavelength metamaterial structure.
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.