Active terahertz metamaterial devices

• Published in: Nature Vol. 444; no. 7119; pp. 597 - 600
• Main Authors: Chen, Hou-Tong, Padilla, Willie J, Zide, Joshua M. O, Gossard, Arthur C, Taylor, Antoinette J, Averitt, Richard D
• Format: Journal Article
• Language: English
• Published: London Nature Publishing 30-11-2006; Nature Publishing Group
• Subjects: Arrays; Construction equipment; Devices; Electric waves; Electromagnetic radiation; Electromagnetic waves; Electromagnetism; Exact sciences and technology; Frequencies; Fundamental areas of phenomenology (including applications); Gold; Infrared, submillimeter wave, microwave and radiowave instruments, equipment and techniques; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Lasers; Materials science; Metamaterials; Methods; Modulation; Modulators; Optical elements, devices, and systems; Optical materials; Optical processors, correlators, and modulators; Optics; Photonic bandgap materials; Physics; Radiation; Real time; Semiconductors; Spectrum analysis; Substrates; Switches; United States; Real time systems; Optical materials; THz range; Optical modulation; Metamaterial
• ISSN: 0028-0836; 1476-4687; 1476-4679
• DOI: 10.1038/nature05343

The development of artificially structured electromagnetic materials, termed metamaterials, has led to the realization of phenomena that cannot be obtained with natural materials. This is especially important for the technologically relevant terahertz (1 THz = 1012 Hz) frequency regime; many materials inherently do not respond to THz radiation, and the tools that are necessary to construct devices operating within this range-sources, lenses, switches, modulators and detectors-largely do not exist. Considerable efforts are underway to fill this 'THz gap' in view of the useful potential applications of THz radiation. Moderate progress has been made in THz generation and detection; THz quantum cascade lasers are a recent example. However, techniques to control and manipulate THz waves are lagging behind. Here we demonstrate an active metamaterial device capable of efficient real-time control and manipulation of THz radiation. The device consists of an array of gold electric resonator elements (the metamaterial) fabricated on a semiconductor substrate. The metamaterial array and substrate together effectively form a Schottky diode, which enables modulation of THz transmission by 50 per cent, an order of magnitude improvement over existing devices.