One-dimensional photonic crystal-based optical diodes for pulse sources

Abstract

This study explores the non-reciprocal characteristics of one-dimensional photonic crystals with Weyl semimetals, exposed to Gaussian laser pulses, utilizing the transfer matrix method. The non-reciprocity of the structure is examined by analyzing the impact of three variables on the contrast and the power ratio of transmitted to input: the pulse carrier frequency's relative position to the defect modes' peak frequency, the pulse duration, and the number of defect layers. The results indicate that by adjusting the carrier frequencies close to the defect mode frequency and minimizing the pulse width so that its power spectrum matches the defect mode frequency width, one can achieve both high contrast and a high transmitted-to-input power ratio. Moreover, increasing the number of defect layers extends the frequency range for high contrast but diminishes the power ratio. These insights are valuable for the design of non-reciprocal photonic devices.