Lettner Thomas, Zeuner Katharina D, Schöll Eva, Huang Huiying, Scharmer Selim, da Silva Saimon Filipe Covre, Gyger Samuel, Schweickert Lucas, Rastelli Armando, Jöns Klaus D, Zwiller Val
Department of Applied Physics, Royal Institute of Technology, Albanova University Centre, Roslagstullsbacken 21, 106 91 Stockholm, Sweden.
Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, 4040 Linz, Austria.
ACS Photonics. 2020 Jan 15;7(1):29-35. doi: 10.1021/acsphotonics.9b01243. Epub 2019 Dec 19.
We develop a structure to efficiently extract photons emitted by a GaAs quantum dot tuned to rubidium. For this, we employ a broadband microcavity with a curved gold backside mirror that we fabricate by a combination of photoresist reflow, dry reactive ion etching in an inductively coupled plasma, and selective wet chemical etching. Precise reflow and etching control allows us to achieve a parabolic backside mirror with a short focal distance of 265 nm. The fabricated structures yield a predicted (measured) collection efficiency of 63% (12%), an improvement by more than 1 order of magnitude compared to unprocessed samples. We then integrate our quantum dot parabolic microcavities onto a piezoelectric substrate capable of inducing a large in-plane biaxial strain. With this approach, we tune the emission wavelength by 0.5 nm/kV, in a dynamic, reversible, and linear way, to the rubidium D line (795 nm).
我们开发了一种结构，用于高效提取由调谐到铷的砷化镓量子点发射的光子。为此，我们采用了一种宽带微腔，其背面有一个弯曲的金镜，该金镜通过光刻胶回流、电感耦合等离子体中的干式反应离子蚀刻和选择性湿法化学蚀刻相结合的方法制造。精确的回流和蚀刻控制使我们能够实现焦距为265 nm的短焦距抛物面背面镜。所制造的结构产生了预测（测量）的63%（12%）的收集效率，与未处理的样品相比提高了一个多数量级。然后，我们将量子点抛物面微腔集成到能够诱导大面内双轴应变的压电基板上。通过这种方法，我们以动态、可逆和线性的方式将发射波长调谐到铷D线（795 nm），调谐速率为0.5 nm/kV。
