[Design and Optimization of Surface Plasmon Resonance Sensor Based on Side Polished Single-Mode Fiber].

Fiber-coupling surface Plasmon resonance sensor has attractive advantages of information transmission such as small volume, anti-electric magnetic field interference, and online real-time remote detection. In order to improve the performance of the sensor, the effect of the residual fiber thickness and the silver film thickness to the sensitivity of the sensor and the depth of the resonance peaks and full width ar half maximum (FWHM) are analyzed respectively. The results show that the increasing fiber residual thickness weakens the SPR phenomenon, and that the increasing silver film thickness widens the resonance peak, while the sensitivity of the sensor does not change monotonously. Through the integration of refractive index sensing sensitivity and full width at half maximum, figure of merit is presented and regarded as the optimized objective. The optimal design is achieved in the case of the fiber residual thickness for 66. 5 µm, and the silver film thickness for 50 nm. The optimized design with the figure of merit of 98. 67 is expected to be applied in the bio-chemical sensing and analysis.

[Spectra modulated surface plasmon resonance sensor based on side polished multi-mode optical fiber].

Surface plasmon resonance, which utilizes the resonance of optical evanescent wave with the metal surface plasmon wave, has been developed into a high sensitivity, rapid, label-less measurement method for chemical and biological analysis. In order to improve the spectral sensitivity in refractive index for a side polished fiber surface plasmon resonance sensor, the whole cladding layer and part of core of a multimode fiber was polished off. Additionally, an extra chrome layer with relatively high refractive index was coated on the polished zone before a gold film. The results showed that the sensor can measure the refractive index range from 1.333 to 1. 431 RIU, with the average spectral sensitivity of 4.11 x 10(3) nm RIU(-1), which is better than the reported results. Especially, in the refractive index range of 1. 417 1. 431 RIU, the sensitivity reaches to 1.09 x 10(4) nm RIU(-1). The minimum resolution of approximately 3.6 x 10(-5) RIU was estimated by a combination analysis with the sensor sensitivity and stability. The superiorities possessed by the proposed sensor in high sensitivity, wide detection range, small size and good stability and reproducibility, etc., make it a good candidate for food testing, environmental monitoring, biomedical testing and other related fields.

[Performance of wavelength modulation surface plasmon resonance biosensor].

Surface plasmon resonance (SPR) is a rapid, label-free, high-precision technique of biological sensing and analysis. The investigation on the characteristics of provides theoretical basis and instructions for the applications of SPR A Kretschmann-structure surface plasmon resonance (SPR) biosensor based on wavelength modulation was developed, and also its sensing performances in the bulk solution was investigated. Measurements with different concentrations of bulk ethanol and ethylene glycol solutions show that the resonant wavelength shows a low sensitivity, but a higher linear response to the change in refractive index (RI), when RI is relatively smaller. With increasing refractive index , the sensitivity of resonance wavelength to changes in the refractive index increases. In the refractive index range of 1. 407 0-1. 430 RIU, sensitivity reaches to 11 487 nm RIU-1. The sensor resonance wavelength stability is 0. 213 8 nm, and the minimum resolution of refractive index approaches to 10-6 RIU. The advantages of the surface plasmon resonance sensor developed here results in simple operation, high sensitivity, wide detection range, low resolution, makes it an important candidate in chemical and biological sensing.

[Rapid detection of alanine aminotransferase with near-infrared spectroscopy].

Near infrared transmission spectroscopy of Whole blood are investigated with different thickness (0.5, 1, 2, 4 mm) in order to explore the feasibility of detecting alanine aminotransferase rapidly by near-infrared spectra. The results show that the whole blood sample with 0.5 mm thickness is more suitable for spectral analysis. And then Near infrared spectroscopy of 176 samples were collected. Multiplicative scatter correction and second-order differential method have been used to spectral pretreatment. Stepwise multiple linear regression method and partial least squares regression method have been employed to establish quantitative detection model to predict content of alanine aminotransferase in whole blood. The alanine aminotransferase measured presents best result in calibration and prediction by Near-Infrared Spectroscopy with partial least squares regression calibration model, and the calibration correlation coefficient, the standard error of calibration and the standard error of prediction are 0.98, 2.42 and 7.22 respectively.

[Application of fiducial wavelength method in processing spectra of turbid media].

In the present paper, the authors analyzed the absorption and scattering effects of changing the solution concentration on the spectra, and dealed with the wavelength, where the absorption and scattering effects counteract completely, the fiducial wavelength method can eliminate the perturbation from shift of instrument and temperature, and also can improve predicting ability of the model. The result of utilizing this method to process the spectral data of two sample sets, i. e. intralipid solution and plasma solution with different level glucose, has verified that fiducial wavelength method can improve correlation coefficient and decrease RMSEP of predicting model.