摘要
近年來，光子晶體共振腔由於擁有高Purcell效應已被頻繁地使用以提升單光子源效率，利於未來量子密碼與通訊等應用。當光子晶體共振腔操作在單模的狀態，量子點產生的光子皆經由這單一的模態釋放出腔體，提升了量子點與模態的耦合效率有利達成高效率的光源。本研究使用的quasi-L2光子晶體共振腔體除了具有極低模態體積適合用以追求高Purcell效應外，更僅提供清晰可辨的三個模態以利於單模操作結構的設計。本研究進一步地對基本quasi-L2結構作幾何條件上的調變，成功地實現波長為1.3 ?m的單模操作quasi-L2光子晶體共振腔。實驗結果顯示，於品質因子1100且共振模態與量子點完全重合的情況下，量子點發光強度整整被提升70倍之多，極適合用以提升單光子源之效率。

Abstract
In recent years, photonic crystal defect cavity is widely used to achieve high Purcell factor for high efficiency single photon sources. As the defect cavity is operated at single mode condition, all the photons generated inside the cavity are forced to funnel through this single mode and lead to enhanced coupling efficiency. Previous study shows that a quasi-L2 defect cavity offers not only three clearly resonant modes but also a very small mode-volume, which is essential for high Purcell effect. In this study, we adjust the geometric parameters of quasi-L2 photonic crystal defect cavity, and successfully realize a 1.3??m single mode photonic crystal cavity. For a cavity with quality factor of 1100, the quantum dot luminescence intensity is enhanced over 70 fold, demonstrating its potential of q-L2 photonic crystal cavity for high efficiency single photon sources and lasers.

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