Papers by Keyword: Reflection Spectrum

Abstract: Through researching we can draw two conclusions. One conclusion is controlling the symmetric and asymmetric atomic - photon coupling interaction is a good way to control the transmission spectrum of incident light. Another conclusion is that multi-frequency photon attenuator can be controlled by asymmetric atomic - photon coupling interaction.

Abstract: In traditional purity detecting system, the purity of gem is determined by depending on the obtained shape of the reflection spectrum and the different shape features. Once gem is mixed, the system cannot accurately identify the aliasing and deformation reflection spectrum, and the accuracy rate of detection is low. A detection system for the purity of gem based on aliasing spectrum splitting algorithm is proposed. By extracting the detection spectrum characteristic parameter of the gem, the superposition and correlation for spectrum characteristic parameter is calculated; aliasing spectrum information is made splitting to classified achieve the purity detection of gem. Experiments show that this method improve the accuracy rate of the purity detection, and achieves satisfactory results.

Abstract: Due to strong coupling among multi-channels of phase-only sampled gratings, the effects of manufacturing errors on sampled grating are different from fiber gratings with a single reflection peak. The influence was investigated by numerical simulation. When group delay and reflectivity ripples are caused by random phase and amplitude errors, inside a grating channel, the ripple amplitude at short wavelength is larger than the one at long wavelength, and this phenomenon was qualitatively explained using the principle that the reflecting position varies with the wavelength of incident light in a chirp grating. The sub-grating length of the transfer matrix method, which is decided by the accuracy of phase mask and UV writing, exerts an influence on the ripple amplitude. For multi-channel fiber gratings, stitch error impairs the periodicity of sampling function, so this kind of fabrication error leads to unequal performance reduction in different channels, and the reduction is more serious for channels at two sides.

Abstract: The reflection spectrum of Methyl Red (MR) doped PMMA film is measured and modified. The refractive index of the sample is gained by calculation of Kramers- Kronig relation with the data of the reflection spectrum. The refractive index change of the sample is gained with the absorption specta. The MR doped PMMA sample has a refractive index change under 532nm laser excitation, in which the valley value happens around 400 nm and peak value around 600 nm. This result shows that the MR doped PMMA sample has an obvious photo induced refractive index change, especially at 400nm and 600nm.

Abstract: In the paper a new method is presented to simulate the course of light output from organic light emitting device. The method uses optical transmission matrix to deal with multiple layers. To confirm the validity of our theories, a comparison of the theoretic analysis with testing results is given. The calculated curve consistented with the experimental value. By this methoed the Commission Internationale de L'Eclairage （CIE） coordinates of device were simulated. By adjusting the thickness of each layer in organic light emission diode (OLED) we obtained different CIE coordinates. When thickness becomes thicker the CIEX becomes bigger on the other hand CIEY become smaller.

Abstract: Dyed Wood is rapidly degraded by short-wavelength UV radiation, and its degree of discoloration correlate well with the wave length. In the paper we test this hypothesis and analyze chemical change of dyed wood surface affected by UV radiation. So that it will be beneficial for further study on synthesis of photo stabilizer. In this research, dyed veneers are irradiated by artificial light using an ultraviolet accelerated weathering device including 5 different wavelengths (UV to visible). CIE (1976) L*a*b* color measuring system is applied to describe the photo-induced discoloration process of dyed veneer. The reflection curves of spectrum and K-M difference spectra show the diverse change of light absorption and reflection. The results reveal that, samples color is great influenced by 313nm and 340nm UV light, the color stability of dye stuffs is rapidly decreased while stimulated by 254nm UV light. The fastness of dyed veneer has a positive relationship with dye stuffs, Acid Red GR dyed veneer just suffer slight yellowing due to the stability of dye, while Acid Blue V dyed veneer fade obviously and get a tendency of reddish.

Abstract: A novel immunosensor based on porous silicon (PSi) for antigen detection was reported in this paper. The antigen (SpaA) and the specificity of the antibodies are employed as the target and the probe in our laboratory, respectively. The immunosensor structure was prepared using bioconjungation. After the antigen-antibody reaction, the red shift of the reflection spectrum of the immunosensor increases in proportion to the concentration of SpaA. The sensitivity of this immunosensor is 41nm/ µg•ml-1 and the detection limit is 2.44×102pg•ml-1, they are better compared with our previous work by using this method. Controlled experiments were also presented with non-immune antibody and the results show that this immunosensor possesses high specificity.