Active terahertz metamaterial devices
| DWPI Title: Terahertz radiation modulating apparatus used in surface emitting quantum cascade laser, excites electrons in substrate to modulate resonance of array of ring resonators while passing current through gap formed in ring resonators |
| Abstract: Metamaterial structures are taught which provide for the modulation of terahertz frequency signals. Each element within an array of metamaterial (MM) elements comprises multiple loops and at least one gap. The MM elements may comprise resonators with conductive loops and insulated gaps, or the inverse in which insulated loops are present with conductive gaps; each providing useful transmissive control properties. The metamaterial elements are fabricated on a semiconducting substrate configured with a means of enhancing or depleting electrons from near the gaps of the MM elements. An on to off transmissivity ratio of about 0.5 is achieved with this approach. Embodiments are described in which the MM elements incorporated within a Quantum Cascade Laser (QCL) to provide surface emitting (SE) properties. |
| Use: Terahertz radiation modulating apparatus for use in surface emitting quantum cascade laser (claimed). |
| Advantage: The transmissive ratio of modulating apparatus is improved and fabrication of the modulating apparatus is performed easily by using a simple structure. |
| Novelty: The apparatus (10) has an excitation unit that excites electrons in a semiconductor substrate (12) for modulating resonance of array of multi-loop split ring resonators (16), while passing current through gap formed in the ring resonators. A metamaterial structure comprising multiple loops of conductive material is arranged in the gap of the ring resonator and exciting of electric contacts (14a,14b) e.g. ohmic contact and Schottky contact formed on the substrate is performed by irradiating laser beam. |
| Filed: 4/3/2009 |
| Application Number: US2009418064A |
| Tech ID: SD 12021.0 |
| This invention was made with Government support under Contract No. DE-NA0003525 awarded by the United States Department of Energy/National Nuclear Security Administration. The Government has certain rights in the invention. |
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