Jinjiang Cui

Analysis of sharpness Fano resonance curve based on eye-like resonators

For given intrinsic losses of a single ring resonator sensor, there exists the maximum sharpness, at the extinction ratio of -6dB. However, the maximum sharpness of a single ring resonator sensor is sensitive for the coupling coefficient. In order to obtain the maximum sharpness, the coupling region of the single rings must have a higher precision of manufacture. To solve this problem, this paper proposed eye-like resonator which is formed by a ring resonator (named inner loop) embedd in the dual-bus-coupled ring resonator (named outer loop). Eye-like resonators can generate the asymmetric Fano-resonance spectra of the drop port, numerical calculation of spectra on the drop port is utilized by the transfer matrix method. As the round trip loss varies, the maximum value of sharpness and the corresponding transmission at the resonant point can be obtained by tuning the phase ratio of the outer loop to the inner loop. The maximum value of sharpness increases with the round trip loss, as the outer loop and inner loop coupling coefficient changing, the maximum value of sharpness of Fano-resonance change slowly in a wide range. As the round trip loss and coupling coefficients of the outer loop and inner loop varies, the corresponding transmission at the resonant point remains almost the same, about -6dB. The sharpness of Fano resonant peak is insensitive for the coupling coefficients, which can reduce the requirements of manufacture of coupling region.

LIBS: A new method for heavy metal in biomedical field and applied in plasma medical

Laser induced breakdown spectroscopy (LIBS) is characterized by non-contract and real-time analysis, which can meet the need of high-speed and automatic in industry and agriculture production and biomedical field. In this paper, the lead concentrations of samples included in glass, pig blood and so on are determinate by LIBS, based on a Nd: YAG Q-switched pulse with wavelength 1064 nm as an exciting source and nongated CCD in common spectrograph as detector. The energy of pulse on the surface of samples is about 100mJ and the width of pulse is 12ns. By the detection of different samples, we definite the detection limit of lead in samples is found to be 0.0074% and the LOD in theory is 0.0074% based on the LIBS system of the instruments all made in China. We found that the difference between the common pig blood and the organic pig blood is the content of K. The results suggest that the accuracy of determination of lead meets the challenge of quantitative analysis and the CCD can displace the ICCD which is very expensive as detector. The feasibility and low cost of the method which uses common spectrometer and CCD to realize the LIBS detection is proved by the result and our investigation will be beneficial to the LIBS application in biomedical field and food safety.