Opt Lett. 2018 Jun 1;43(11):2555-2558. doi: 10.1364/OL.43.002555.
In this study, we report a low-symmetric photonic crystal (PhC) structure that exhibits high coupling efficiency in a broadband frequency range with a tilted self-collimating capability. First, the analytical approach is implemented as a starting point, and the ideal configuration is chosen for the self-collimation effect, which is analytically supported by group velocity dispersion and third-order-dispersion calculations. Then, numerical analyses in both time and frequency domains are performed to the ideal PhC design, which possesses a strong self-collimating characteristic, even at huge incident angles within the operating frequencies. Later, experimental measurements are conducted in microwaves, and the existing self-collimation property is still preserved at longer wavelengths in the millimeter scale. The microwave experiment as well as numerical analyses indicate that the designed PhC self-collimator allows overcoming possible misalignment problems at the PhC-source interface and enables a strong broadband beam channeling with a high transmission.
在这项研究中，我们报告了一种低对称光子晶体（PhC）结构，它在宽带频率范围内表现出高耦合效率，并具有倾斜自准直能力。首先，我们采用解析方法作为起点，并选择理想的配置来实现自准直效应，这一效应得到了群速度色散和三阶色散计算的支持。然后，我们对理想的 PhC 设计进行了时域和频域的数值分析，结果表明即使在工作频率内存在较大的入射角，该设计也具有很强的自准直特性。之后，我们在微波波段进行了实验测量，结果表明在毫米波段的较长波长处仍然存在自准直特性。微波实验和数值分析表明，所设计的 PhC 自准直器可以克服 PhC 源接口处可能存在的对准问题，并实现具有高传输率的强宽带光束导。
