砷化銦/砷化鎵微碟共振腔之光學特性研究

Abstract

本論文探討由砷化銦量子點作為發光主動層之微碟共振腔螢光光譜。藉由顯微光激螢光光譜，分析不同直徑之微碟共振腔譜線，可辨別出其為耳語廊模態。透過解析解近似法的計算與三維有限時域差分法的模擬，我們可正確標示出實驗量測耳語廊模態之方位角與徑向模態數。激發光強度對譜線的影響與品質因子分析也將一併討論。由時間解析光譜量測結果，我們觀察到室溫下量子點之自發性輻射率受到量子點與共振腔之弱耦合效應而提升。透過顯微光激螢光技術對微碟共振腔之空間解析光譜量測，發現了不同模態數的耳語廊模態，其空間上有方向性的螢光強度分佈。使用近場顯微光學技術，則可觀察到微碟共振腔表面耳語廊模態的場型分佈與模態數。

The optical properties of microdisk (MD) microcavities with embedding InAs QDs in GaAs membrane are investigated. The emission spectra of the MD microcavities of different sizes are observed by micro-photoluminescence (μPL) measurements. A number of shape emission lines have been characterized as the whispering-gallery modes (WGMs). Analytic approximation method and three-dimensional finite-difference time-domain (3D-FDTD) simulations are used to identify the azimuthal and radial mode numbers of the measured WGMs. Power dependent and time-resolved μPL measurements have also been performed and discussed. Spontaneous emission enhancement is observed at room temperature, which is attributed the weak coupling regime. Directional radiation patterns are observed by μPL intensity mapping contour plots. Near-field resonance patterns of different WGMs measured by scanning near-field optical microscopy (SNOM) technique are also presented.