本文介绍了采用一种新型的Bragg 光纤（蜘蛛网结构包层空芯光纤）解决塑料光纤损耗大的历程。蜘蛛网结构包层空芯光纤比现有文献报道的各种空芯光纤具有明显的优越性，能大幅度降低材料吸收的影响，从而能利用有损耗的塑料，实现从紫外到毫米波之间各种波长、各种性能（单模、圆偏振、低损耗等）的塑料光纤；与此同时，采用从原料到挤出以及连续拉纤工艺，可以实现低成本、大批量生产，实现从性能到成本全面解决塑料光纤损耗大的世界性老大难问题。

A model that describes the multiphoton interaction of a two-level atom with a large period quantized standing wave field beyond the Raman-Nath regime is solved exactly by the Wei-Norman’s operator factorization method, and the momentum distribution of the atom is discussed. We also investigate the dynamics of the atomic population inversion and field second-order correlation function. They exhibit very remarkable behavior due to the inclusion of atomic translational motion.

By introducing an additional air hole into the center of each unit cell of the conventional honeycomb lattice, a new kind of structure that can support air guidance of light with low-order bandgaps is proposed. Numerical investigation indicates that, due to the generation of the lower order bandgaps, larger air-guiding photonic bandgaps (PBGs) than those of triangular structures can be achieved in the new structures. Furthermore, the proposed structures also provide additional freedom in tailoring PBGs.