Low-threshold amplification of spontaneous emission from AgInS2 quantum dots

Abstract

Recently, solution-processed conventional I–III–VI₂ quantum dots (QDs) demonstrated a potential optical amplification application based on superior optical properties. Nonetheless, exploiting the potential of this type of material as a gain medium for optical amplification devices is still scarce, rendering application prospect restricted. Herein, for the first time, we report the amplified spontaneous emission (ASE) action using AgInS₂ (AIS) QDs as the gain medium. ASE with an ultra-low threshold (31.58 μW cm⁻²) was demonstrated by combining highly reflective distributed Bragg reflectors (DBR) with AIS QDs. Furthermore, the relationship between the number of layers of the DBR mirrors and the ASE performance is systematically discussed, indicating that the seven-layer DBR is a desirable device structure with the best ASE from AIS QDs. These consequences unambiguously uncover the significant feasibility of the traditional AIS QDs as a photonic resource, simultaneously demonstrating the huge potential and promising applications of as-designed devices for optical amplification.