Efficient light amplification in low gain materials due to a photonic band edge effect

L Ondič,I Pelant

doi:10.1364/oe.20.007071

Abstract

One of the possibilities of increasing optical gain of a light emitting source is by embedding it into a photonic crystal (PhC). If the properties of the PhC are tuned so that the emission wavelength of the light source with gain falls close to the photonic band edge of the PhC, then due to low group velocity of the light modes near the band edge caused by many multiple reflections of light on the photonic structure, the stimulated emission can be significantly enhanced. Here, we perform simulation of the photonic band edge effect on the light intensity of spectrally broad source interacting with a diamond PhC with low optical gain. We show that even for the case of low gain, up to 10-fold increase of light intensity output can be obtained for the two-dimensional PhC consisting of only 19 periodic layers of infinitely high diamond rods ordered into a square lattice. Moreover, considering the experimentally feasible structure composed of diamond rods of finite height - PhC slab - we show that the gain enhancement, even if reduced compared to the ideal case of infinite rods, still remains relatively high. For this particular structure, we show that up to 3.5-fold enhancement of light intensity can be achieved.

Highlights

Photonic crystals (PhCs) are materials possessing a periodicity in refractive index which offer control of the way light propagates in the medium [1, 2]
We show that even for the case of low gain, up to 10-fold increase of light intensity output can be obtained for the two-dimensional PhC consisting of only 19 periodic layers of infinitely high diamond rods ordered into a square lattice
We showed that by introducing the periodicity into the refractive index of the active material, the intensity of light propagating through the structure composed of only 19 periodic layers can be increased by factor varying from 1.5 up to 10

Summary

Introduction

Photonic crystals (PhCs) are materials possessing a periodicity in refractive index which offer control of the way light propagates in the medium [1, 2]. They are extensively studied because of their interesting optical properties which can be used to prepare photonic waveguides [3, 4], cavities [5], couplers [6] or outcouplers [7,8,9] of light and other optical devices with dimensions comparable or smaller than the wavelengths of light that they are designed for. In this article, we will focus only on periodic structures

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