利用闪耀光栅作为外腔光反馈元件，研究Littrow结构的蓝紫光外腔半导体激光器。通过引入闪耀光栅，在光栅面和半导体激光器后端面之间构成耦合外腔，改善了中心波长位于405.5 nm的边发射半导体激光二极管的性能。研究结果表明，在引入外腔反馈后，半导体激光二极管的阈值电流降低了27%，说明外腔与内腔之间具有较高的耦合效率；改变反馈元件光栅的转角，实现了激射波长的宽带连续调谐，调谐范围可达7 nm。

Commercially available blue-violet edge-emitting semiconductor laser diode with a wavelength of 405.5 nm is characterized and then operated in an external cavity with a Littrow configuration in our laboratory. A resonant cavity is formed between the blazed grating and the rear facet of the laser diode, which improves the performance of the laser diode greatly. The results show that the threshold current of the semiconductor laser diode decreases by 27%, indicating high coupling efficiency between the external cavity and inner cavity. Besides, by changing the angle of the blazed grating, the total wavelength tuning range can reach up to 7 nm.