ACOFT ANZCOP SPIE Melbourne 2019 RF Single Sideband Generator

We demonstrate an orthogonally polarized optical single sideband (OP-OSSB) generator based on dual cascaded micro-ring resonators (MRRs). We achieve a large tuning range of the optical carrier to sideband ratio of up to 57.3 dB. The operation RF frequency of the OP-OSSB generator can also be continuously tuned with a 21.4 GHz range via independent thermal control of the two MRRs.

Electromechanically Rotatable Cross-Shaped Mid-IR Metamaterial

We present an electromechanically rotatable infrared (IR) cross-shaped metamaterial (CSM) in the mid-IR wavelength range. The CSM configuration is composed of double gold layers with cross-shaped nanostructures. To investigate the fano-resonance within CSM nanostructures, the aspect ratios and length ratios of CSM are compared and discussed. The electromagnetic responses exhibit the characteristics of large tuning range, tunable broad and narrow bandwidths. By properly tailoring the aspect ratio of CSM, the resonance can be tuned with bidirectional tuning in the range of 650 nm. CSM with different length ratios exhibit narrowband resonances around the wavelength of 4.6 μm and broadband resonances in the wavelength range of 5.0 μm to 6.5 μm. These characteristics of CSM with different aspect ratios and length ratios could be potentially used in IR narrowband and broadband filter. To further increase the flexibility of proposed electromechanically rotatable CSM, an actively tunable narrowband and broadband filter in the mid-IR wavelength range is performed. This study provides a unique approach to realizing an IR filter, with high flexibility.

Reconfigurable All Dielectric Metasurfaces based on Optical Phase Change Materials: Design Approaches

Optical metasurface is a recently emerged paradigm for controlling light propagation, which enables implementation of ultra-compact optical devices with extended functionalities. Nowadays the main challenge in the field is to realize active metasurfaces with high quality, high efficiency, and large tuning range. Here we present a design approach for constructing a two-state reconfigurable metalens made of low-loss optical phase-change material (O-PCM). The metalens design is capable to produce diffraction limited focusing, large change in focal length (from 1.5 mm to 2mm), and decent focusing efficiency of about 20% in both states. The proposed design methodology is generic and can be easily extended towards constructing metasurfaces, which can switch between two or more arbitrary phase maps.

A Compact Frequency Reconfigurable Hybrid DRA for LTE/Wimax Applications

A compact hybrid antenna structure with frequency reconfiguration capabilities is presented in this article. The proposed design employs a combination of a rectangular DR element and a coupling slot on the structure’s ground plane (GP). The slot shifts the fundamental DRA mode by introducing a slow wave effect and its resonant behavior helps to achieve an omnidirectional pattern at low frequencies. The slot is loaded with a series of PIN diode switches whose ON/OFF combinations alter the effective slot length. Slot loading with PIN diodes results in frequency reconfiguration of the proposed structure with a large tuning range of 76.2% (between 1.73 and 3.86 GHz). A parametric analysis was performed to investigate the effects of slot length, width, and position on the reflection coefficients of the proposed structure. A prototype of the proposed design was fabricated and results were measured. The measured results show a close agreement with the simulated ones. The proposed design is suitable for DCS 1800 MHz, PCS 1900 MHZ, UMTS, LTE 2500–2700 MHz, and Wimax 3.5 GHz.