Conventional concentrators with inhomogeneous coating materials that fully enclose the destined region pose great challenges for fabrication. In this paper, we propose to design an EM concentrator with homogeneous materials. Distinguished from conventional ones, the elaborately designed EM concentrator features a concentrator region that is open to the outer-world, which is achieved with multi-folded transformation optics method by compressing and folding the coating materials to create window(s). Based on this concept, we also investigate open-rotator and open rotational-concentrator devices, which could simultaneously rotate and store the EM waves in the central destined region. Due to the open nature of our proposed designs, we believe they will find potential applications in remote controlling with impressive new functionalities.

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GaN based Photonic Integrated Circuits (PICs) have now become a global contender for their wide range of applications owing their physical characteristics. The GaN material system acts as a promising platform; compatible with silicon and sapphire substrates. Both the carrier transport and carrier removal techniques are vital to develop the efficient platform for the integration of photonic circuits. We demonstrate the carrier removal mechanism in silicon (Si) doped GaN (0001) epitaxially grown on c-plane sapphire wafer using ion engineering of the devices. Ion-engineered regions within the active layers of the device are modelled, fabricated and characterized to assess the isolation created. Helium and Carbon ions with predesigned doses and energies are used to irradiate the device structures. We have modelled and fabricated ion-engineered regions within the active layers and studied the carrier transport properties on said regions to isolate that particular part with either of active photonic components placed at the common platform. After ion irradiation, detailed analysis in terms of electric field dependent current characteristics, sheet resistance, carrier mobilities, activation energies, dark and photo currents under zero (ground) and multiple biases are examined to see the extent of charge leakage and to map the charge behavior under nominal operation. Device characteristics under wide regime of annealing temperatures ranging from 300 • C to 1000 • C are mapped to evaluate the thermal stability of implant driven isolated regions. Activation energies of implanted and parent regions has also been studied. The dark and photon driven electric currents at ground and under biased have been measured to investigate the photo-induced transport phenomenon.INDEX TERMS Ion implantation, electrical isolation, photonic integrated circuits, crosstalk.

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