砷化鎵光子晶體面射型雷射特性之研究

Abstract

在這篇論文中，我們成功以電子束微影系統製作出砷化鎵光子晶體面射型雷射，並研究其光學特性。本次實驗中所使用的樣品為使用分子束磊晶矽統(MBE)所製作的砷化鎵晶片，其中包括三對的GaAs/InGaAs多重量子井，其發光波段位於900 nm到1000 nm之間。光子晶體的晶格常數為285 nm，空氣孔洞的形狀為圓形及直角三角形。本次研究的動機為研究兩種不同形狀空氣孔洞的雷射特性，包括其雷射特性以及使用變角度螢光量測系統量測其光子晶體能帶圖，並且以平面波展開法、三維耦合波理論以及商用軟體COMSOL分析實驗結果。在最後的結果中，實驗顯示使用直角三角形孔洞其雷射閾值較大，但其出光效率較圓形孔洞來的高。並且，在實驗中也觀察到許多不同階數的橫向傳遞模態，造成雷射的大角度出光。透過改變不同的孔洞幾何形狀，可以達成不同的雷射特性。未來可進一步製作高功率電激發砷化鎵光子晶體雷射，並研究不同磊晶結構對雷射出光特性的影響。

In this thesis, we have demonstrated GaAs-based photonic crystal surface emtting laser (PCSEL) and the laser characteristics were also measured and analyzed. The wafers made by molecular beam epitaxy (MBE) were used. The photonic crystal lattice constant is designed at 285 nm, and the main lasing peak is located at wavelength 950 nm, which is due to the Bragg’s condition. The air hole shape of the photonic crystal are circular and right triangular. The results show that the photonic crystal surface emitting laser with right triangular air hole has higher threshold density but higher light output efficiency. The angular resolved photoluminescence measurements also show that the structure has multi-guided modes coupled with each other, resulting in large angle laser emission. Through changing the geometry of the air holes of photonic crystal, the laser characteristics can be adjust. We will expect to discuss the further results by fabricating the high power electrically pumped photonic crystal surface emitting lasers in the future.