C-band operating plasmonic sensor with a high Q-factor/figure of merit based on a silicon nano-ring.

In this paper, we take advantage of the high refractive index property of silicon to design a practical and sensitive plasmonic sensor on a photonic integrated circuit (PIC) platform. It has been demonstrated that a label-free refractive index sensor with sensitivity up to 1124 nm/RIU can be obtained using a simple design of a silicon nano-ring with a concentric hexagonal plasmonic cavity. It has also been shown that, with optimum structural parameters, a quality factor (Q-factor) of 307 and a figure of merit (FOM) of 234R I U -1 can be achieved, which are approximately 8 times and 5 times higher than the proposed sensors counterparts, respectively. In addition, the resonance mode of the hexagonal cavity with Si nano-ring (HCS) sensor can be adjusted to operate in the C-band, which is a highly desirable wavelength range in terms of compatibility with devices in PIC technology.

Integrated vortex beam emitter device for optical manipulation.

In this study, we provide a theoretical overview for the potential of the integrated vortex beam emitter (IVBE) in optical tweezer applications. To the best of our knowledge, this is the first attempt in the literature to investigate the optical tweezing property of IVBE. The finite-difference time-domain numerical analysis technique has been utilized for the transverse optical trapping calculations. The results show that the basic IVBE device generates an optical force of an order of 10-16N, which can be increased up to 10-15N with the duty cycle adjustment. Therefore, this work emphasizes that the IVBE device can provide a compact, efficient, low-cost, and practical optical tweezing ability.

Fast hydrogen detection via plasmonic metal-insulator-metal technology.

In this study, a nanoscale sensor on a metal-insulator-metal (MIM) platform was studied numerically to investigate its hydrogen detection potential. The plasmonic MIM structure, which consists of an air micro-ring resonator (MRR) and a palladium (Pd) disk, is used for this purpose. The results of the numerical study show that when the optimum geometric design parameters are employed, a sensitivity as high as 267 pm/(v/v-% hydrogen) can be obtained. In addition, a response time of 172.125 s could be achieved, which is calculated according to the second law of Fick. The result of the study can lead future studies to design fast and high-precision hydrogen gas sensors on a nano-scale base.

Integrated optical vortex beam receivers.

A simple and ultra-compact integrated optical vortex beam receiver device is presented. The device is based on the coupling between the optical vortex modes and whispering gallery modes in a micro-ring resonator via embedded angular gratings, which provides the selective reception of optical vortex modes with definitive total angular momentum (summation of spin and orbital angular momentum) through the phase matching condition in the coupling process. Experimental characterization confirms the correct detection of the total angular momentum carried by the vortex beams incident on the device. In addition, photonic spin-controlled unidirectional excitation of whispering-gallery modes in the ring receiver is also observed, and utilized to differentiate between left- and right-circular polarizations and therefore unambiguously identify the orbital angular momentum of incident light. Such characteristics provide an effective mode-selective receiver for the eigen-modes in orbital angular momentum fiber transmission where the circularly polarized OAM modes can be used as data communications channels in multiplexed communications or as photonic states in quantum information applications.