Abstract-One-way edge modes in truncated semiconductor photonic crystal at terahertz frequencies

Lingjuan He, Linfang Shen, Xiaohua Deng, Kai Yuan,

https://iopscience.iop.org/article/10.1088/2040-8986/ab1bcd/pdf

Terahertz one-way edge modes in truncated photonic crystals (PhCs) are investigated theoretically. The PhC consists of a square array of air columns in semiconductor. By applying an external dc magnetic field in the PhC, a band gap is generated by lifting the degeneracy point of the lowest two bands. Based on this band gap, edge mode always exists in the truncated PhC for any boundary cutting, and it may propagate unidirectionally or bidirectionally, closely depending on the PhC boundary shape. It is shown that for one-way edge mode, the PhC boundary cutting has remarkable influence on the propagation length when the semiconductor loss is taken into account. A boundary structure is introduced into the PhC system for weakening the loss effect, and the propagation length of the one-way edge mode can be increased nearly by twice by optimizing the boundary parameters.

Abstract-One-way edge modes in a photonic crystal of semiconductor at terahertz frequencies

Lingjuan He, Qian Shen, Jie Xu, Yun You, Tianbao Yu, Linfang Shen, Xiaohua Deng,

https://www.nature.com/articles/s41598-018-26395-4

Electromagnetic edge mode in a photonic crystal (PhC), which is a square array of semiconductor rods in air, is theoretically investigated for terahertz frequencies. In the PhC, gyroelectric anisotropy is introduced in the semiconductor rods by applying an external magnetic field and consequently, a degeneracy point, at which two dispersion surfaces intersect, is lifted and a new band gap is created. The edge mode sustained by the PhC possesses the character of one-way propagation, and it even can be immune to backscattering at large defect on the wavelength scale and 90° sharp bend. The properties of the one-way mode are closely dependent on the cladding layer structure of the PhC.