An approach to achieve all-angle, polarization-insensitive and broad-band self-collimation in 2D square-lattice photonic crystals

作者：Noori M^*; Soroosh M; Baghban H

来源：Ukrainian Journal of Physical Optics, 2015, 16(2): 85-94.

DOI：10.3116/16091833/16/2/85/2015

• self-collimation
• photonic crystals
• equal-frequency contours
• optical integrated circuits

We have investigated the possibility for achieving (in the same structure), an all-angle, polarization-insensitive and broad-band self-collimation (SC), one of the most urgent requirements in the field of optical integration. To obtain these attractive SC features in 2D square-array photonic crystals, we have used several strategies and performed testing calculations, using plane-wave expansion and finite-difference time-domain methods. We have not complicated the basic structure for the SC and ensured its simple geometry. The all-angle SC can arise when the optical material of a hole-type structure is high-index. Our results have testified that the SC in the hole-type structure is less dependent on the light polarization, if compared with a similar rod-type one. Our optimized SC structure has a bandwidth of Delta f/f(c) = 2.61% and supports the all-angle SC for both TE and TM polarizations at the expense of small (similar to 3 degrees) deviation of light from the unique collimation direction. Notice that the latter can be tolerated in many integrated optical devices.

• 出版日期2015