光子晶體共振腔有很高的自發性輻射耦合因子（spontaneous emission coupling factor ,β），因此應用在量子點雷射時可以有效的降低自雷射的臨界功率，引起許多團隊的興趣。本論文研究q-L2共振腔，在室溫下利用微螢光量測系統（μ-PL）量測發現β由0.5-0.75，而臨界功率為6-12μW。也因為二維光子晶體量子點雷射有高的自發性輻射耦合因子，使得臨界功率時附近時螢光強度緩慢的上升（Soft turn-on），在臨界功率附近時光譜半高寬變窄的趨勢也較為緩慢。利用麥克森干涉儀量測光源的同調長度，也因為麥克森干涉儀使得在研究二維光子晶體量子點雷射時，除了微螢光量測系統，多了一項工具可以研究光子晶體雷射的雷射特性。 Owing to the spontaneous emission coupling factor (β) in photonic crystal cavity, it can efficiently reduce the lasing threshold in quantum dots laser. In this paper, we will investigate qL2 cavity. By the measurement of micro-photoluminescence (μ-PL) in room temperature, the β of qL2 cavity are around 0.5~0.75, and the lasing threshold are around 6~12μW. Owing to the high β of photonic crystal quantum dots laser, the light-in light-out curve show the soft turn-on behavior around the threshold, and narrowing degree of the line-width is not obvious around the threshold. We study coherence property of light source by measuring coherence length in using Michelson interferometer. In addition to the μ-PL system, adding another way to study Laser property photonic crystal laser.
