| CPC G02F 1/0147 (2013.01) [G01J 1/0407 (2013.01); G02F 1/17 (2013.01)] | 26 Claims |
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1. A reconfigurable optical frequency selective structure comprising embedded therein:
(a) an array of optical antennas for picking up propagating radiation in a visible or infrared frequency region and achieving preferential absorption of electromagnetic energy at a target wavelength k within the region, the array of optical antennas being of sub-wavelength scale and being separated from one another at a predetermined pitch or pitches;
(b) an array of optical mesa structures of sub-wavelength scale, including at least first and second optical mesa structures, each optical mesa structure in the array of optical mesa structures comprising a phase-change material, the phase change material comprising a chalcogenide-containing alloy, the array of optical antennas being disposed atop the array of optical mesa structures respectively;
(c) a metal ground plane disposed beneath the array of optical mesa structures or, optionally, beneath an interfacial layer disposed between the metal ground plane and the array of optical mesa structures, the array of optical mesa structures standing above the ground plane or the interfacial layer and being separated from one another to inhibit parasitic capacitance coupling therebetween; and
(d) means for selectively heating any selected one of the array of optical mesa structures to cause the phase change material in the selected optical mesa structure to change from an amorphous state in which the antenna atop the selected optical mesa structure is capacitively coupled to the metal ground plane to a crystalline state in which the antenna atop the selected optical mesa structure is electrically shunted to the metal ground plane via the selected optical mesa structure:
wherein, with the antenna atop the selected optical mesa structure capacitively coupled to the metal ground plane the selected optical mesa structure provides the optical frequency selective structure with an optical response and, with the antenna atop the selected optical mesa structure electrically shunted to the ground plane the selected optical mesa structure does not provide the optical frequency selective structure with an optical response; and
wherein components (a), (b), (c) and (d) are configured and arranged such that the optical frequency selective structure is reconfigurable in at least four (4) different optical configurations, including a configuration in which the first and second optical mesa structures provide the optical frequency selective structure with first and second optical responses respectively, a configuration in which neither of the first and second optical mesa structures provides the optical frequency selective structure with an optical response and configurations in which only one or the other of the first and second optical mesa structures provides the optical frequency selective structure with an optical response.
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