Airy-type X-ray states generated using 3/2 flat diffractive optics.

X-rays have developed into an essential tool in variety of fields, such as biology, materials, chemistry, and physics etc. Numerous X-ray types, including the orbital angular momentum (OAM), the Laguerre-Gauss, and the Hermite-Gauss states, have been proposed. This greatly enhances the depth of application of X-ray. The X-ray states described above are mostly produced by binary amplitude diffraction elements. In light of this, this paper proposes a flat X-ray diffraction grating based on caustic theory to generate Airy-type X-ray. It is proved by the simulation of multislice method that the proposed grating can generate the Airy beam in the X-ray field. The results show that the generated beams have a secondary parabolic trajectory deflection with the propagation distance, which is consistent with the theory. Inspired by the success of Airy beam in light-sheet microscope, the Airy-type X-ray can be anticipated to enable novel image capability for bio or nanoscience.

Enhanced lighting on the road surface with TIR-PA optical element on tunnel sidewall.

Both the lighting quality and driving safety inside the tunnel have been quite a concern around the world. In this study, a plate with prism array of total internal reflection (TIR-PA) has been designed to enhance the lighting on the road surface inside the tunnel in adherence to traffic safety as well as energy savings. Such optical elements, above the tunnel sidewall, can redirect the rays emitted from both the headlight and lighting devices to the road surface, which supports higher flux on the road. Simultaneously, the simulation is conducted with consideration of practical factors based on the mathematical model and edge-ray principle to attain the effect of the TIR-PA plates. On the one hand, for the rays from the lighting devices, the enhancement rate of illuminance has reached 12.60%-16.58%, which is attributed to TIR-PA plates above the different sidewalls of the Lambertian scattering property. TIR-PA can be suitable for various sidewall materials due to the small effect of illumination reduction. On the other hand, 30.2%-32.2% rays of the headlight source received by the sidewall, due to the effect of TIR-PA plates, are redirected to the driving distance for 27.3-71.9 m, which makes 15.9-31.1m2 of road surface brighter. It makes contributions to the improvement of illuminance distribution and drivers' pre-judgment. In the future, broader applications regarding the TIR-PA plates will be explored widely in tunnel lighting systems due to the low production cost.