A novel photonic crystal (PC) all-optical switch based on the shift of defect mode is demonstrated. Two photonic crystal waveguides are connected by a photonic crystal cavity. The point defect of the photonic crystal cavity is filled with phenylacetylene liquid cyrstals intermingled with azobenzene. The output of the optical switch is controlled by adjusting the rotation angle of the liquid crystals' orientation vector. And the optical switch is numerically investigated by using the finite difference time domain (FDTD) method and plane wave expansion method. Numerical simulation shows that the optical switch based on the PC cavity can be changed by adjusting the applied linearly polarized light. Results show that the switch has low threshold power density, great extinction ratio, and small size.
The black-nickel film on the flat type radiometer chip was investigated, and a black-nickel film which can be applied in this chip was prepared using electroplating method. The analyses of absorption of radiometer chip indicated that the absorption rate of the chip is proportional to the surface roughness. The black-nickel film was prepared and tested, and surface morphology testing showed that this film has microstructures of the scale 50 nm—1.5 μm. Infrared absorption measurement indicated that the absorptivity of the film in the 1.4—8 μm range is higher than 0.989. This high absorptivity black-nickel film improves the performance of the chip.
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