Double Electromagnetically Induced Transparency and Its Slow Light Application Based On a Guided-Mode Resonance Grating Cascade Structure.

Guofeng Li,Lingjun Zhou,Yuyu Tao,Junbo Yang,Zhenrong Zhang,Huimin Huang,Zhaojian Zhang,Yunxin Han

doi:10.3390/ma13173710

Guofeng Li, Lingjun Zhou + Show 6 more

Open Access

https://doi.org/10.3390/ma13173710

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Abstract

In recent years, the achievement of the electromagnetically induced transparency (EIT) effect based on the guided-mode resonance (GMR) effect has attracted extensive attention. However, few works have achieved a double EIT-like effect using this method. In this paper, we numerically achieve a double EIT-like effect in a GMR system with a three-layer silicon nitride waveguide grating structure (WGS), using the multi-level atomic system model for theoretical explanation. In terms of slow light performance, the corresponding two delay times reach 22.59 ps and 8.43 ps, respectively. We also investigate the influence of wavelength detuning of different GMR modes on the transparent window and slow light performance. Furthermore, a wide-band flat-top transparent window was also achieved by appropriately adjusting the wavelength detuning between GMR modes. These results indicate that the EIT-like effect in the WGS has potential application prospects in low-loss slow optical devices, optical sensing, and optical communications.

Highlights

The electromagnetically induced transparency (EIT) effect is caused by quantum interference of different excitation paths in a three-level system; it is one of the important technologies to achieve the slow light effect [1,2]
Sun-Goo Lee developed the EIT-like effect based on the guided-mode resonance (GMR) effect in a waveguide grating structure (WGS), which contains two planar dielectric waveguides and a sub-wavelength grating [17], where the transparent window appears in the transmission dip by coupling high-Q and low-Q resonance modes in different dielectric waveguides
We reported a double EIT-like effect with two high Q values in a GMR system, where both waveguide layers have two dielectric gratings in one period, and two narrow-band transparent windows appear in the two transmission dips on account of the coupling of different GMR modes [21]

Summary

Introduction

The electromagnetically induced transparency (EIT) effect is caused by quantum interference of different excitation paths in a three-level system; it is one of the important technologies to achieve the slow light effect [1,2]. Sun-Goo Lee developed the EIT-like effect based on the guided-mode resonance (GMR) effect in a waveguide grating structure (WGS), which contains two planar dielectric waveguides and a sub-wavelength grating [17], where the transparent window appears in the transmission dip by coupling high-Q and low-Q resonance modes in different dielectric waveguides. We reported a double EIT-like effect with two high Q values in a GMR system, where both waveguide layers have two dielectric gratings in one period, and two narrow-band transparent windows appear in the two transmission dips on account of the coupling of different GMR modes [21]. We present the effect of wavelength detuning of different GMR modes on the position of the transparent window and slow light performance by changing the grating width. This work paves the way for high-performance slow light devices and has potential applications in optical communications

Materials and Methods

Results

At the resonance wavelength of EITof

Discussion

The transmission and delay time underdifferent different W

Conclusions