Wei Luo

Bio: Wei Luo is an academic researcher from Chinese Academy of Sciences. The author has contributed to research in topics: Surface plasmon resonance & Surface plasmon. The author has an hindex of 4, co-authored 7 publications receiving 56 citations.

Dual-angle technique for simultaneous measurement of refractive index and temperature based on a surface plasmon resonance sensor

Abstract: We describe a theoretical model to analyze temperature effects on the Kretschmann surface plasmon resonance (SPR) sensor, and describe a new double-incident angle technique to simultaneously measure changes in refractive index (RI) and temperature. The method uses the observation that output signals obtained from two different incident angles each have a linear dependence on RI and temperature, and are independent. A proof-of-concept experiment using different NaCl concentration solutions as analytes demonstrates the ability of the technique. The optical design is as simple and robust as conventional SPR detection, but provides a way to discriminate between RI-induced and temperature-induced SPR changes. This technique facilitates a way for traditional SPR sensors to detect RI in different temperature environments, and may lead to better design and fabrication of SPR sensors against temperature variation.

Simultaneous measurement of refractive index and temperature for prism-based surface plasmon resonance sensors

Abstract: A detailed theoretical model is provided to analyze the effects of temperature on prism-based surface plasmon resonance (SPR) sensors, including temperature dependence of the metal and prism. A complete sensitivity matrix simultaneously measures variations in refractive index (RI) and temperatures using measurements at two wavelengths for the angular-interrogation mode, or at two angles of incidence for the wavelength-interrogation mode. Correction of matrix coefficients improves accuracy of the two modes. Validation is performed using a self-designed wavelength SPR system with an adjustable incident angle perform. This method provides a new way to detect the RI and may lead to the better design and fabrication of prism-based SPR sensors.

Rapid fabrication of micro-nanometric tapered fiber lens and characterization by a novel scanning optical microscope with submicron resolution.

Abstract: In numerous applications of optical scanning microscopy, a reference tapered fiber lens with high symmetry at sub-wavelength scale remains a challenge. Here, we demonstrate the ability to manufacture it with a wide range of geometry control, either for the length from several hundred nanometers to several hundred microns, or for the curvature radius from several tens of nanometers to several microns on the endface of a single mode fiber. On this basis, a scanning optical microscope has been developed, which allows for fast characterization of various sub-wavelength tapered fiber lenses. Focal position and depth of microlenses with different geometries have been determined to be ranged from several hundreds of nanometers to several microns. FDTD calculations are consistent with experimental results.

Rapid and controllable in-site synthesis method and device of optical fiber core end silver nanoparticles

Abstract: The invention discloses a rapid and controllable in-site synthesis method and device of optical fiber core end silver nanoparticles. According to the method and device, by stimulating light source strength and modulating irradiation time, the sizes and distribution of the nanoparticles are controllable. The method that the silver nanoparticles are synthetized at the optical fiber core ends can be expanded to multi-core optical fibers to manufacture silver nanoparticle arrays, the method and the Rman probe label technique are combined, multiple articles to be analyzed are detected simultaneously, and alternatively multi-channel detection of one specific article to be analyzed is achieved. The method is easy to operate, a manufacturing process is rapid, controllable and low in comprehensive cost, the synthetized silver nanoparticles and an optical fiber Raman enhance spectrum can be combined perfectly, and very good application value in chemical analysis and biological detection is obtained.

A Quantum Dot Fluorescence Sensor System Design for Hg²⁺ Trace Detection.

Abstract: The detection of Hg²⁺ ions usually requires large laboratory equipment, which encounters difficulties for rapid field test in most applications. In this paper, we design a reflective sensor for trace Hg²⁺ analysis based on the fluorescent quenching of Quantum dots, which contains two major modules, i. e. the fluorescent sensing module and the signal processing module. The fluorescence sensing module is composed of a laser source, a light collimated system and a photo-detector, which enables the realization of the fluorescence excitation as well as its detection. The signal processing module realized the further amplification of the detected signal and hereafter the filtering of noises. Furthermore, the Hg²⁺ concentration will displayed on the QT interface using a Linux embedded system. The sensor system is low cost and small, which makes it available for rapid field test or portable applications. Experimental results show that the sensor has a good linear relationship for the Hg²⁺ concentration range from 15.0 x 10⁻⁹ to 1.8 x 10⁻⁶ mol · L⁻¹. The regression equation is V₀/V = 1.309 13 + 3.37c, where c is Hg²⁺ concentration, and V₀ is the voltage value for the blank case. In our work, the linearity is determined as 0. 989 26. The experiments exhibit that Ca²⁺, Mn²⁺ and Pb²⁺ ions have small influence on the Hg²⁺ detection, and the interfere of other common ions can be neglected, which indicates a good selectivity of the sensor. Finally, it shows that our sensor has a rapid response time of 35 s and a good repeatability, thus it is potential for field test of trace Hg²⁺.

Wavelength-scale light concentrator made by direct 3D laser writing of polymer metamaterials

Abstract: We report on the realization of functional infrared light concentrators based on a thick layer of air-polymer metamaterial with controlled pore size gradients. The design features an optimum gradient index profile leading to light focusing in the Fresnel zone of the structures for two selected operating wavelength domains near 5.6 and 10.4 μm. The metamaterial which consists in a thick polymer containing air holes with diameters ranging from λ/20 to λ/8 is made using a 3D lithography technique based on the two-photon polymerization of a homemade photopolymer. Infrared imaging of the structures reveals a tight focusing for both structures with a maximum local intensity increase by a factor of 2.5 for a concentrator volume of 1.5 λ3, slightly limited by the residual absorption of the selected polymer. Such porous and flat metamaterial structures offer interesting perspectives to increase infrared detector performance at the pixel level for imaging or sensing applications.