In this paper, we propose and numerically study a subwavelength grating based hybrid plasmonic waveguide. The metal layer on top of the waveguide enables unique features compared with conventional silicon based waveguide. Since the field distribution in this structure is different, traditional homogeneous medium approximation is not applicative. Therefore, we develop a new effective index calculation method. This method is suitable for metal-existing waveguide as well as structures with multiple medium. Effective index of this waveguide depends on grating period, duty ratio and width, respectively. By modifying duty ratio and period of the waveguide, the relationship between effective index and waveguide width can be concave function or convex function and the slope can be similar to TM mode of silicon based waveguide, which opens up possibilities for SPPs based applications.
Molecular imaging techniques are becoming increasingly important in biomedical research and potentially in clinical practice. We present a continuous-terahertz (THz)-wave molecular imaging system for biomedical applications, in which an infrared (IR) laser is integrated into a 0.2-THz reflection-mode continuous-THz-wave imaging system to induce surface plasmon polaritons on the nanoparticles and further improve the intensity of the reflected signal from the water around the nanoparticles. A strong and rapid increment of the reflected THz signal in the nanoparticle solution upon the IR laser irradiation is demonstrated, using either gold or silver nanoparticles. This low-cost, simple, and stable continuous-THz-wave molecular imaging system is suitable for miniaturization and practical imaging applications; in particular, it shows great promise for cancer diagnosis and nanoparticle drug-delivery monitoring.
Using the split-step Fourier method, the nonlinear effects and higher-order dispersion in optical fiber are studied and
numerically analyzed. Based on the analysis, the theoretical model of higher-order dispersion compensation with phased
modulator is presented, with emphasis on the third-order dispersion. According to the theoretical model, simulation
models based on VPItransmission is designed. Finally, experimental schemes are designed, and experiment is finished:
200-fs pulses propagate through a 47-km fiber link, including a 39.8-km SMF (single-mode fiber) and a 6.71-km DCF
(dispersion-compensation fiber). In that experiment, the oscillating tails are completely suppressed and the third-order
dispersion is successfully compensated with the phase modulator. Moreover, the parameters of modulator are optimized
with VPItransmission Modeling.