(b) Wavelength at 763 nm. (c) Wavelength at 769 nm. (d) Wavelength at 760 nm. (e) find more info Wavelength …The resonant wavelength for the TM mode is 766 nm. Similarly, incident light is only changed 3 nm, to 763 nm and 769 nm, and the corresponding electric field distributions, shown in Figure 3(b,c), respectively, change slowly. Figure 3(d,e) shows the electric field distribution at 760 nm and 772 nm, respectively, which have sharp electric field distribution changes, but exhibit lower intensity. Using the RCWA method, the FWHM for the TE mode is ~20 nm while the TM mode’s FWHM is ~4 nm. Due to this contrast, the conclusion is that the energy distribution of the TM mode is more concentrated than the TE mode, so the TM mode is more sensitive than the TE mode.
The different electric field distribution for TE and TM mode is due to the different waveguide eigenvalue equations for different polarization cases. If the effective mode propagation constant of the i-th order evanescent diffracted wave in the waveguide grating is given by:��i,v=k0(ncsin��-i��/��)(2)The mode propagation constant can be obtained by solving the classical eigenvalue equation for the homogeneous slab waveguide given by [15]:tan(ki,vd)=ki,v(��i,v+��i,v)ki,v2-��i,v��i,v(3)where the Z-components of the wave number in the cover, grating, and substrate regions are described by:��i,v=(��i,v2-nc2k02)1/2,��i,v=(nav2k02-��i,v2)1/2,��i,v=(��i,v2-ns2k02)1/2(4)respectively.
A similar argument applies for the TM polarization case, and thus the waveguide eigenvalue equation for the TM polarization case is given by:tan(ki,vd)=nav2ki,v(ns2��i,v+nc2��i,v)nc2ns2ki,v2-nav4��i,v��i,v(5)where GSK-3 the according refractive index of co
Flow and transport processes in the unsaturated or vadose zone control the time and degree of groundwater pollution because the surface-applied chemicals need to pass this zone first to be able to reach groundwater. The factors or processes taking place in this zone are numerous and complex due to the soil heterogeneity. Advanced experimental or modeling tools are required to understand the mechanisms of such complex flow and transport processes. Such tools allow us to develop good management practices to protect soil and groundwater from contamination because of the land-applied chemicals, like agricultural fertilizers and pesticides.
Water and solutes can move through MEK162 side effects the vadose zone along preferred pathways, such as soil cracks, worm holes, and root channels [1,2]. This non-equilibrium phenomenon, known as preferential flow, causes contaminants to reach great depths through these large openings in the soil in relatively short times [3�C5]. Unlike uniform flow, preferential flow causes irregular wetting of the soil profile due to water moving faster in certain parts of the soil profile than the other parts [6�C8].