Development of reconfigurable metamaterial Terahertz filters by selective optical pumping of vanadium dioxide

Date

2020-12

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Abstract

Development of terahertz (THz) transmission and reception technologies has lead to studies concerning a wide range of applications, such as in imaging, security, pharmacy and medicine. Studies of THz frequencies have also lead to the development of various types of passive filters that can modulate THz frequencies. These filters mostly consist of two or more types of materials stacked in layers and are thus called metamaterial THz filters. Although there has been significant progress in the development of new metamaterial filters, the amplitude modulation performance of most of these filters is fixed by their design and cannot be altered once fabricated. This thesis will present the details of the development of an optical system that can produce a reconfigurable THz metamaterial filter. The system uses a spatial light modulator to modulate an infrared laser into reconfigurable patterns and then projects these patterns onto a thin layer of vanadium dioxide (VO2) film. These reconfigurable laser patterns selectively transform the VO2 film into a metamaterial filter having a bandwidth whose frequency can be easily tuned. The spatial light modulator was built from a pico-projector and employs a digital micromirror device (DMD) chip to modulate light. Different types of laser patterns were produced the experiment and their consistency with the input patterns was observed using a CCD camera and a micrometer scale. The transformation of the VO2 film was observed using an infrared camera and captured in photos.

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Keywords

Terahertz filters, Vanadium dioxide

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