Abstract
The utilization of UV excitation to verify the terahertz (THz) wave modulation of hexagonal-shaped metamaterial (MM) arrays coated with synthesized photoluminescent, down-shifting ZnO quantum dots (QDs) of two different radius sizes, namely, 3.00 nm (pH 10) and 2.12 nm (pH 12), respectively is reported. In order to characterize the behavior of the MM before and after deployment of the ZnO QDs, THz time domain spectroscopy in transmission mode was employed. Upon exposure to UV excitation, the collected amplitude modulation values were 9.21% for the pH 12 and 4.55% for the pH 10 ZnO QDs, respectively. It is anticipated that the ability to actively tune the performance of otherwise passive structures will promote the proliferation of THz signal modulation devices in the near future.
Highlights
The terahertz (THz) portion of the electromagnetic spectrum is located between the microwave and infrared segments and has remained relatively underdeveloped because the power output of conventional electronic circuitry (i.e., IMPATT, MMIC, Gunn, TUNNET, multiplexers, photomixers, RTD, etc.) drops significantly as the transition is made from the microwaves to the THz region
The utilization of UV excitation with a wavelength of 400 nm, to verify the modulation of THz waves of a metamaterial array coated with previously synthesized photoluminescent, down-shifting ZnO quantum dots (QDs) synthesized in colloidal solutions with pH values of 10 and 12, respectively, is discussed in this work
The THz time domain spectroscopy (THz-TDS) characterization was performed by employing a Menlo Systems TeraSmart equipment [25], operated in transmission mode
Summary
The terahertz (THz) portion of the electromagnetic spectrum is located between the microwave and infrared segments and has remained relatively underdeveloped because the power output of conventional electronic circuitry (i.e., IMPATT, MMIC, Gunn, TUNNET, multiplexers, photomixers, RTD, etc.) drops significantly as the transition is made from the microwaves to the THz region. Incorporating functional materials to MM designs capable of responding in real time to an external stimulus would improve tunability and, more generally, enable the demonstration of THz modulation devices [12] by modifying signal intensity, phase, propagation direction, beam shape or resonant frequency. To this end, the utilization of UV excitation with a wavelength of 400 nm, to verify the modulation of THz waves of a metamaterial array coated with previously synthesized photoluminescent, down-shifting ZnO QDs synthesized in colloidal solutions with pH values of 10 and 12, respectively, is discussed in this work
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