量子點輻射與微碟共振腔模態之耦合研究

Abstract

本計畫擬研究量子點輻射與微碟共振腔之細語迴廊模態耦合，並應用於 量子點量子光源之開發。主要研究方向包括：(1)以外加磁場調控單量子點與 微共振腔之耦合強度；(2)高品質因子微碟共振腔製作及量子點腔體-量子電 動力學；(3)第二型量子點與微共振腔耦合之載子動力學；(4)量子點與雙微 共振腔之耦合研究；(5) 微共振腔與光纖側向波導之耦合研究。首先，利用 電感式耦合電漿蝕刻技術及適當的製程改良，我們目標製作高品質因子 (>20000)之微碟共振腔，使其與單量子點的二能階系統達到強耦合。除了以 改變溫度來調控耦合強度外，本研究將利用磁場來改變量子點輻射波長， 使其與微碟共振腔模態產生共振。利用超快時間解析光激螢光光譜量測以 及時間解析激發相干量測，將可研究量子點在共振腔中的量子電動力學效 應，包括強耦合及弱耦合作用。此外，我們也將嘗試讓第二型量子點與共 振腔產生耦合，研究共振腔對第二型量子點載子動力學的影響。本計畫亦 目標製作雙微碟共振腔，使雙微碟模態因耦合而形成光子分子態。最後， 我們將發展以光纖側向波導耦合微碟共振模態的技術，達到共振激發量子 點的目標。側向光纖可牽引出共振腔的模態，而形成“飛行＂量子位元， 進而使其傳遞於兩個腔體量子電動力學系統之間。

The proposal is devoted to the study of resonant couplings between quantum dot (QD) emissions and whispering-gallery modes of microdisk (MD) cavities for the development of QD-based quantum light sources. Proposed research topics are: (1) Using externally applied magnetic field to manipulate the coupling strength between QD emissions and the MD cavity modes; (2) Fabrication of MD cavities with high quality factors (Q factor) for the study of QD cavity-quantum electrodynamics (c-QED); (3) Carrier dynamics of type-II QDs in MD cavities; (4) Interactions of QD with coupled modes of double-disk cavities; (5) Lateral coupling of MD cavity emissions using fiber taper waveguides. In order to enter the strong coupling regime, we will use our inductively-coupled-plasma reactive-ion-etching (ICP-RIE) system and optimized recipes to fabricate high-Q MD cavities (Q>20,000). Apart from the conventional temperature tuning of QD-cavity coupling, we propose to use externally applied magnetic field to manipulate the emission energy of single QDs for matching resonant modes of MD cavities. By using the time-resolved photoluminescence and time-resolved excitation correlation measurements, the effects of c-QED in either the strong or the weak coupling regimes on the QD-cavity system will be comprehensively investigated. In addition to conventional InAs QDs, we will also incorporate type-II InAs/GaAsSb QDs in MD cavities to investigate the effects of cavity coupling on the carrier dynamics of type-II QDs. Finally, the technique of lateral coupling of cavity emissions by fiber taper waveguides will be developed, by which the cavity emission can be drawn out to act as a flying quantum bit transferring among different QD-cavity systems.