Cyclodextrin Polymer Films Optical Waveguide Sensor for Volatile Organic Gas Detection

A sensitive optical waveguide（OWG） sensor which can be used to detect volatile organic compounds（VOCs） was presented.The sensing device（element） was fabricated by means of the immobilization of polyvinyl pyrrolidone（PVP）-cyclodextrin（CD） composite film over a single-mode potassium ion exchanged glass OWG via spin-coating method.The sensor shows higher response to styrene gas than to other VOCs and displays a linear response to styrene gas in a range of 1―1000 μL/L.

Experimental Study on Near-IR Nonlinear Optical Waveguide Sensor for Refractive Index of Liquids

To determine the refractive index of liquids in near infrared（lR）, a method is presented by measuring the output angle of the visible Cerenkov-radiation-mode when liquids are placed as the cover on a planar lithium niobate waveguide. The system configuration and the principle of the method are analyzed and some experimental results are given out. Both the experimental result and simulation show that this method is simple, rapid and of sufficient precision.

The Sensitivity of TE Filed Propagating in LHM-Antiferromagnetic Sensor

A three-layer waveguide structure sensor consists of LHMs （left-handed materials） film surrounded by dielectric cladding and antiferromagnetie substrate is proposed. LHMs known as MTMs （metamaterials） have simultaneous negative permeability and permittivity. The dispersion relation for the structure is derived for TE guided modes. Two ranges of frequencies are chosen such that Voigt permeability,μv, either negative or positive. The sensitivity is proven to be affected by different parameters including the film thickness, LHM parameters, and Voigt frequency.

Simple Raman scattering sensor integrated with a metallic planar optical waveguide: effective modulation via minor structural adjustment

We report experimental realization of Raman spectra enhancement of copper phthalocyanine, using an on-chip metallic planar waveguide of the sub-millimeter scale. The oscillating ultrahigh order modes excited by the direct coupling method yield high optical intensity at resonance, which is different from the conventional strategy to create localized ＂hot spots.＂ The observed excitation efficiency of the Raman signal is significantly enhanced,owing to the high Q factor of the resonant cavity. Furthermore, effective modulation of the Raman intensity is available by adjusting the polymethyl methacrylate（PMMA） thickness in the guiding layer, i.e., by tuning the light–matter interaction length. A large modulation depth is verified through the fact that 10 times variation in the enhancement factor is observed in the experiment as the PMMA thickness varies from 7 to 23 μm.

Refractive Index Sensor Based on Metal-Clad Planar Polymer Waveguide Operating at 850nm

A metal-clad planar polymer waveguide refractive index sensor based on epoxy(EPO)polymer materials by using light intensity interrogation at 850 nm is designed.The polymethyl methacrylate(PMMA)material is deployed as the low refractive index(RI)buffer layer in order to better couple the optical guided mode and the surface plasmon polaritons(SPP)mode for working in water environment.The effects of the gold film thickness,PMMA buffer layer thickness,waveguide layer thickness,waveguide width,and gold length on the sensor sensing characteristics have been comprehensively studied.Simulation results demonstrate that the normalized transmission increases quasi-linearly with the increment of RI of the analyte from 1.33 to 1.46.The sensitivity is 491.5 dB/RIU,corresponding to a high RI resolution of 2.6×10^(9)RIU.The designed SPP-based optical waveguide sensor is low-cost,wide-range,and high-precision,and has a broad application prospect in biochemical sensing with merits of miniaturization,flexibility,and multiplexing.