Active Terahertz Nanoantennas Based on VO₂ Phase Transition

Abstract

Unusual performances of metamaterials such as negative index of refraction, memory effect, and cloaking originate from the resonance features of the metallic composite atom [1][2][3][4][5][6] . Indeed, control of metamaterial properties by changing dielectric environments of thin films below the metallic resonators has been demonstrated [7][8][9][10][11] . However, the dynamic control ranges are still limited to less than a factor of 10, 7-11 with the applicable bandwidth defined by the sharp resonance features. Here, we present ultra-broad-band metamaterial thin film with colossal dynamic control range, fulfilling present day research demands. Hybridized with thin VO 2 (vanadium dioxide) 12-18 films, nanoresonator supercell arrays designed for one decade of spectral width in terahertz frequency region show an unprecedented extinction ratio of over 10000 when the underlying thin film experiences a phase transition. Our nanoresonator approach realizes the full potential of the thin film technology for long wavelength applications.

Mechanically Tunable Dielectric Resonator Metasurfaces at Visible Frequencies

“…13 The metasurface tunability can also be achieved by manipulating the nearfield interactions via varying unit cell periods. [14][15][16][17] Other methods to achieve tunable metasurfaces or metamaterials include the use of phase-change materials, 18,19 voltage-controlled coupling, 20 and thermal stimulus. 21 Incorporating resonant elements on stretchable substrates enables mechanical tuning of the optical responses of metasurfaces.…”

Characteristics of terahertz wave modulation using wavelength-selective photoexcitation in pentacene/Si and TIPS pentacene/Si bilayers

“…[1][2][3][4] The development of THz devices and systems over the last decade was largely based on the application of new materials such as metamaterials, plasmonic structures, graphene, metal oxides, and organic-based materials. [5][6][7][8][9][10] In particular, technologies utilizing new materials are preferentially applied for developing active THz modulators because the devices that can temporarily control the THz waves are absolutely essential for wireless communication and highly functional sensing/imaging systems. [6][7][8][9][10][11][12][13][14][15] Realizing the perfect modulation depth in THz transmission is a key technology for active THz modulators.…”

“…[5][6][7][8][9][10] In particular, technologies utilizing new materials are preferentially applied for developing active THz modulators because the devices that can temporarily control the THz waves are absolutely essential for wireless communication and highly functional sensing/imaging systems. [6][7][8][9][10][11][12][13][14][15] Realizing the perfect modulation depth in THz transmission is a key technology for active THz modulators. Several methods for achieving near-perfect modulation efficiency of THz transmission using VO 2 -based plasmonic nanoslots, integrated graphene layers, conjugated polymers, and organicbased hybrid structures were reported.…”

“…Several methods for achieving near-perfect modulation efficiency of THz transmission using VO 2 -based plasmonic nanoslots, integrated graphene layers, conjugated polymers, and organicbased hybrid structures were reported. 9,[16][17][18][19][20][21] In particular, the technologies based on organic/inorganic hybrid structures enable highly efficient photo-induced modulation of THz wave transmission that is caused by the metallization of an organic layer because of a charge transfer from the silicon (Si) substrate to the organics. 19 This method has advantages such as high modulation efficiency, broadband modulation, and structural simplicity for easy fabrication.…”

Visualizing near-field coupling in terahertz dolmens

“…By exploiting the strong scattering properties of these structures, it is possible to fabricate THz modulators, filters, and beam routing elements, [1][2][3][4][5][6] where the thickness of the devices is a fraction of the wavelength. 7 Such devices can eventually be inserted into emerging implementations of THz optical communications 8 and imaging 9 systems, where the small footprints afforded by resonant structures are appealing in applications.…”