Maksymov, Ivan S.Miroshnichenko, AndreyKivshar, Yuri2016-05-172016-05-171094-4087http://hdl.handle.net/1885/101429We propose and theoretically demonstrate a novel type of optical Yagi-Uda nanoantennas tunable via variation of the free-carrier density of a semiconductor disk placed in a gap of a metallic dipole feeding element. Unlike its narrowband all-metal counterparts, this nanoantenna exhibits a broadband unidirectional emission and demonstrates a bistable response in a preferential direction of the far-field zone, which opens up unique possibilities for ultrafast control of subwavelength light not attainable with dipole or bowtie architectures.This work was supported by the Australian Research Council.© 2012 Optical Society of AmericaKeywords: Bistables; Bow tie; Far-field zones; Free carrier density; Nanoantennas; Narrow bands; Subwavelength lights; Ultrafast control; Optical constants; Optics2012-04-0910.1364/OE.20.0089292016-06-14