Zhou Guorui

Liquid Concentration Sensing Properties of Microfibers with a Nanoscale-Structured Film

A type of compact solution concentration sensor based on a microfiber with a nanoscale-structured film is proposed and demonstrated experimentally Additional loss at different solution concentrations is calculated by means of the three-dimensional finite-difference time-domain (3D-FDTD) method. The microfiber is fabricated by using the flame-heated scanning technique. Nanoscale-structured film is coated on the microfiber surface, which is assembled as a sensing unit. The sensitivity of this kind of sensor increases with the decreasing diameters of the microfiber. When the diameter of the microfiber is 2 ?m, a minimum concentration sensitivity of 1% (under 450 s measuring time) is demonstrated in the experiment. Higher sensitivity can be attained when the solution concentration is higher. The sensing properties of this microfiber with the nanoscale-structured film may provide opportunities for new applications in optical sensing devices.

A Temperature Sensor Based on a Symmetrical Metal-Cladding Optical Waveguide

A compact temperature sensor based on a symmetrical metal-cladding optical waveguide using free-space coupling is proposed and demonstrated theoretically and experimentally. The symmetrical Au-cladding optical waveguide is based on a thin LiNbO3 slab sandwiched between two metal films, which serve as the coupling layer and reflecting panel, respectively. The sensitivity of this sensor of 9.08 × 10−2 deg/°C, 6.6 × 10−2 deg/°C and 4.8 × 10−2 deg/°C corresponding to 3238-order, 3237-order and 3236-order modes, respectively, are obtained. Higher resolution is predicted with a larger linear expansion coefficient material and a higher resolution θ/2θ goniometer.