Precision analysis of turbulence phase screens and their influence on the simulation of Gaussian beam propagation in turbulent atmosphere.

The slip-step method is widely used in simulating optical wave propagation in turbulent atmosphere, which treats propagation and phase perturbations caused by turbulence separately and in discrete steps along the propagation axis. The phase perturbations are represented by a series of phase screens, and hence, the precision of the phase screen concerns the accuracy of the simulation. In this paper, we first discuss the precision and computational performance of phase screens generated by the subharmonic complemented discrete Fourier transformation (DFT) (DFT-SH) method, three kinds of randomized spectral sampling techniques (sparse spectrum (SS) technique, sparse spectrum technique with uniform wave vectors (SU), randomized DFT technique), and optimization-based (OB) method; then, the simulations are implemented with the phase screens generated by these methods.

DERS substrate based on NERS-SERS interaction in integrated microfluidic detection.

The systematic simulation study of a structure with nanogap-enhanced Raman scattering and surface-enhanced Raman scattering (NERS-SERS) substrate is presented. This double-enhanced Raman scattering (DERS) substrate with coupling between the localized surface plasmons of noble metal nanosphere colloids and surface plasmon polaritons of a 1D sinusoidal noble metal nanograting is analyzed. With the excitation light wavelength at 785 nm, the key structure parameters of noble metal nanospheres and sinusoidal noble metal nanogratings are deduced by FDTD.