The Technology Of Surface Plasmon Resonance And Its Application In The Measurement Of The Complex Refractive Index

The technology of Surface Plasmon Resonance (SPR) has wide prospect in clinical diagnosis, biochemical pharmaceutics, environmental detection, etc, as a result of its particular advantages of high sensitivity, non-purification of sample, and the detection with free label, real time as well as non-traumatic. In order to enhance the sensitivity and resolution of the SPR sensor, and extend the application of SPR technology, the systemic and profound researches are implemented theoretically and experimentally on the SPR coupling configuration, the influence of the probe beam's parameters on the performance of the SPR sensor and the application of SPR technology on the absorbing medium detection and so on. In a word, the innovative achievements are listed as follows:By comparison, the performance and applicability of four prism coupling configurations (including the conventional SPR, Longe Range SPR, Coupled Plasmon Waveguide Resonance and Waveguide Coupled SPR) of SPR sensors are analyzed. Based on the numerical simulation, the sensitivity, resolution and linearity measurement range of the different SPR sensors are researched in detail under the angle, wavelength and intensity modulations respectively, when they are used to detect the sample's refractive index variation and the sensing layer's variation of the refractive index or thickness. As expected, all the results are valuable for the configuration design of SPR sensors.The influence of the probe beam's collimated degree, breadth of spectrum line and polarization degree on the SPR sensor is discussed. The results show that the collimated degree is the most notable factor among the three parameters. Concretely speaking, the drop of the collimated degree will not only decrease the resolution but also induce the non-uniformity of reflectivity and sensitivity differences among the probe spots for the imaging SPR sensor based on the intensity detection. Therefore, these results can supply some significant guidance for the source design of the SPR sensor.A new method which determines the complex refractive index of absorbing medium with SPR phase detection is proposed. The complex refractive index of Intralipid solutions (imitating the biological tissues) and leporine blood are experimentally measured by the new proposed method, on the basis of analyzing the biological tissues'optical characters. The simulated results indicate that the measurement uncertainty of the complex refractive index's real and imaginary parts can reach to 10-4. Furthermore, the application of SPR technology in detecting the variation of complex refractive index for absorbing medium is studied based on the Lorentz model. Hence, these researches extend the application range of SPR technology, and provide a possible method that has high-precision in the measurement of the complex refractive index for turbid medium.The transmission character of a two-dimensional and sub-wavelength SPR structure which will be applied to the refractive index sensor is studied. The effect of each parameter on the transmission peak is analyzed and explained theoretically. The results manifest that not only SPR which caused by the period but also the other resonance modes exist in the two-dimensional periodic metal film at the same time. As a matter of fact, a resonant peak which is much sharper than that of the prism coupling SPR can be obtained by adjusting the periodic configuration. Based on which a sensor with better noise-resistance and higher resolving power can be gained. In short, this study can be used in the design of novel SPR sensors.