Guanjun Wang

Design and analysis of a nanostructure grating based on a hybrid plasmonic slot waveguide

A novel nanostructure grating with broadband reflection is proposed and analyzed in this paper. The grating is based on a hybrid plasmonic slot waveguide that consists of a vertical dielectric-slot incorporated at the gap between the upper silicon rib and the metal substrate. The structure could provide an ultra-tight mode confinement in the cross-section while maintaining a relatively low propagation loss. By exploiting the superior modal properties, an ultra-compact and broadband Bragg grating is presented, which shows the capability of efficient wavelength selection near the telecom bandwidths. The waveguide-based Bragg grating could be used as a filter in telecommunication systems and could be a promising candidate for future integrated photonic circuits.

Gas Raman sensing with multi-opened-up suspended core fiber

Gas sensing and fluid-guiding response properties of a suspended core fiber Raman analyzer with side-opened and strut microfluid-guiding array are explored. A Raman sensing model is introduced for effective mode area optimization and normalized intensity overlap enhancement between Raman sensing light and analyte. Calculations predict that there is a trade-off between the overlap and the effective mode area, while the optimal trade-off depends on the refractive index of the background material, core diameter, and struts thickness. Furthermore, the multi-opened-up structure ensures a fast gases diffusing into/out of each hole for real-time Raman sensing. Simulation results confirm a limited gas sensing response time of less than 6 s could be feasible and, thus, a new approach to real-time gas sensing applications is identified.

Silicon-Slot-Mediated Guiding of Plasmonic Modes: The Realization of Subwavelength Optical Confinement With Low Propagation Loss

Waveguiding platforms consisting of metallic nano-wires embedded inside vertical-type dielectric slot waveguides are proposed and the guiding properties are investigated at the telecom wavelength. It is shown that the characteristics of the plasmonic modes can be strongly modified owing to the existence of the silicon rails in close proximity to the metallic nanowire, which enables low-loss light guiding with subdiffraction-limited mode area. Systematical analysis regarding the variation of key geometric parameters has revealed that the symmetric hybrid mode can exist within a wide-range of physical dimensions, and demonstrates improved optical performance over either the conventional hybrid plasmonic mode or the fundamental plasmonic mode supported by a single metal nanowire. Furthermore, we show numerically that the supported symmetric and asymmetric modes can be separately excited through controlling the polarization state of the Gaussian beam that illuminated onto the nanowire tip. The presented hybrid waveguides naturally extend the capabilities of both the silicon slot and metal nanowire structures, which could facilitate a number of potential applications at the subwavelength scale.

Suspended core fiber integrated microfluidic chip for surface plasmon resonance enhanced biosensing

A side-opened suspended core fiber integrated microfluidic chip for surface plasmon resonance enhancement is presented. The influences of fiber size, thickness of Au film, resonance wavelength and fluidic dynamics on the characteristics of the surface enhanced biosensing sensors are investigated.

Fluidic sensor based on the side-opened and suspended dual-core fiber

For accelerating the response and enhancing the sensitivity simultaneously, a novel fluidic sensor based on a side-opened and suspended dual-core fiber and dual-beam interference detection mechanism is first explored and analyzed here. The side opening ensures a fast response by allowing fluidic analyte to approach the fiber core laterally. The dual-beam Mach-Zehnder interferemetry provides a relative higher sensitivity. Calculation results show that a sensitivity of 2.1×10(-6) refractive index unit (RIU) within a response time of 10 s could be achievable, which reflects its potential impact on constructing a fluid refractometer for fast-response and high-sensitivity detection. Moreover, the relationship of the sensing sensitivity and the detected dynamic range of this suspended dual-core fiber structure, polarization, and the transmitting waveband are also analyzed.

A fast response suspended core fiber optical gas sensor with side-opening and micro-holes configurations

A fast response suspended core fiber optical gas sensor configuration using side-opening hole and micro-holes array structure on the thin layers is proposed. The side-opening-hole structure enables a fast filling speed of gases into the opening-up-hole region, while the micro-holes array on the thin layers ensures that gases could further diffuse into the other holes columns quickly. Meanwhile, its sensitivity could be tripled in contrast to the previous structures. Simulation results show that a diffusion limited response time of 12 s could be realized and thus move a step further toward real-time sensing applications.

Compact deep-subwavelength Bragg grating based on hybrid plasmonic slot waveguide

An ultra-compact and broad-band Bragg grating based on HPSW is presented which shows the capability of efficient wavelength selection near the telecom bandwidths. It will have a potential application in the broad-band telecommunications systems.

A fast response tilted fiber Bragg grating fluid refractometer using an exposed-hole microstructured optical fiber

A fast response tilted fiber Bragg grating fluid refractometer using an exposed-hole microstructured optical fiber is proposed and analyzed. The theoretical and simulation results show that a sensitivity of 5.40×10-5 r.i.u within a diffusion limited response time of 6 s could be achieved. This exposed-hole configuration can be used to construct a fluid refractometer for achieving a fast response, high sensitive distributed detection.