Bias-scanning based tunable LSPR sensor.

The principle and the characteristics of the bias-scanning based tunable localized surface plasmon resonance (LSPR) sensors for environmental refractive index have been theoretically and numerically investigated in detail. The sensors exhibit linear negative-shifts in the scattering-bias spectral position when the refractive index of the surrounding medium increases. By bias-scanning, a single-wavelength measurement for sensing the environmental refractive index can be realized effectively. In addition, we demonstrate that the sensing performance of the designed sensor can be adjusted by nano-scale manipulations of metal nanoparticles' sizes and shapes. The proposed devices may pave the way for the development of electrochemical sensors that can convert spectrum scanning into bias scanning.

[Modeling and Simulation of Spectral Polarimetric BRDF].

Under the conditions of the polarized light, The reflective surface of the object is affected by many factors, refractive index, surface roughness, and so the angle of incidence. For the rough surface in the different wavelengths of light exhibit different reflection characteristics of polarization, a spectral polarimetric BRDF based on Kirchhof theory is proposee. The spectral model of complex refraction index is combined with refraction index and extinction coefficient spectral model which were got by using the known complex refraction index at different value. Then get the spectral model of surface roughness derived from the classical surface roughness measuring method combined with the Fresnel reflection function. Take the spectral model of refraction index and roughness into the BRDF model, then the spectral polarimetirc BRDF model is proposed. Compare the simulation results of the refractive index varies with wavelength, roughness is constant, the refraction index and roughness both vary with wavelength and origin model with other papers, it shows that, the spectral polarimetric BRDF model can show the polarization characteristics of the surface accurately, and can provide a reliable basis for the application of polarization remote sensing, and other aspects of the classification of substances.

[The Effect of Observation Geometry on Polarized Skylight Spectrum].

Study on polarized skylight spectral characters while observation geometry changing in different solar zenith angles (SZA), viewing zenith angles (VZA) or relative azimuth angles (RAA). Simulation calculation of cloudless daylight polarimetric spectrum is realized based on the solver, vector discrete ordinate method, of radiative transfer equation. In the Sun's principal and perpendicular plane, the spectral irradiance data, varying at wavelengths in the range between 0.4 and 3 µm, are calculated to extend the atmospheric polarization spectral information under the conditions: the MODTRAN solar reference spectrur is the only illuminant source; the main influencing factors of polarized radiative transfer include underlying surface albedo, aerosol layers and components, and the absorption of trace gases. Simulation analysis results: (1) While the relative azimuth angle is zero, the magnitude of spectrum U/I is lower than 10(-7) and V/I is negligible, the degree of polarization and the spectrum Q/I are shaped like the letter V or mirror-writing U. (2) In twilight, when the Sun is not in FOV of the detector, the polarization of the daytime sky has two maximum near 0.51 and 2.75 µm, and a minimum near 1.5 µm. For arbitrary observation geometry, the spectral signal of V/I may be ignored. According to observation geometry, choosing different spectral bands or polarized signal will be propitious to targets detection.