中国光学期刊网

We report on the fabrication and optimum of lithium niobate planar and ridge waveguide at the wavelength of 633 nm. To obtain a planar waveguide, oxygen ions at the energy of 3.0 MeV with a fluence of 1.5×1015 ions/cm2 are implanted in the polished face of LiNbO3 crystals. For planar waveguide, a loss of 0.5 dB/cm is obtained after annealing at 300 oC for 30minutes. The ridge waveguide is fabricated by diamond blade dicing method on optimized planar waveguide. The guiding properties are investigated by prism coupling and end-face coupling method.

In this work, surface enhanced Raman spectroscopy (SERS) substrates with Ag nanoparticles (NPs) decorated Co₃O₄nanowires (NWs) grafted on the three-dimensional (3D) network architecture of Ni foam (denoted as Ag-NP@Co₃O₄- NW/Ni-foam) arrays are manufactured. In the experiment, the hierarchical Ag-NP@Co₃O₄-NW/Ni-foam arrays exhibit strong SERS activity due to the higher density of the “hot spots” created from the large quantities of neighboring Ag NPs. Using this hierarchical 3D SERS substrates, the crystal violet (a banned drug of aquaculture) with concentration down to 10^-14mol/L can be detected, which shows potential application in SERS-based rapid trace-level detection of harmful food additives.

In this paper, we present the design, simulation, fabrication and characterization of a terahertz (THz) filter based on metamaterial consisting of the periodical double symmetric splits ring resonator (DS-SRR) array. We can observe that the metamaterial-based filter possesses a band-pass transmission when the electrical field is along y direction, and it possesses a low-pass transmission when the electrical field is along x direction. Our results demonstrate that the proposed filter can realize the switching between band-pass effect and low-pass effect by only changing the polarization direction of the incident electromagnetic wave. Moreover, the calculated surface current distributions are also used to analyze the switchable mechanism of the THz metamatrial filter. Therefore, the proposed THz wave filter has a potential application in THz wave communication systems.