由於半導體雷射體積小、效率高且價格相對低廉，於現今已經廣泛應用於日常生活中。然而在高功率下半導體雷射的線寬會增寬，而且頻率容易受到溫度和注入電流影響，這使得這些雷射在物理光學實驗上使用不方便。為了得到窄線寬且頻率可調的雷射，我們採用Littrow架構組成一個外腔式二極體綠光雷射。以往我們要得到一個單頻的綠光雷射需要採用腔內倍頻技術，例如二極管泵浦固態雷射可以發出532 nm的雷射光，但此種雷射體積大且耗能。近年來，二極體雷射可以以氮化銦鎵為材料，直接產生綠光雷射，可望取代傳統的二極管泵浦固態雷射。
本論文我們以綠光二極體雷射作為研究，首先我們以光譜儀分析不同操作電流下雷射的光譜的變化，並且測量外腔式二極體雷射的波長可調範圍。再來我們測量雷射在不同溫度下的輸出特性曲線及外腔式二極體雷射在不同偏振下的輸出效率，最後以掃描法布立-培若干涉儀測量外腔式二極體雷射的線寬。
我們成功製作了一台溫控的綠光外腔式二極體雷射，波長為518 nm，其效率約為52%。在25°C、兩倍閾值電流時輸出功率為41.9 mW，初步估算線寬約為10.3 MHz。
關鍵詞：外腔式二極體雷射，Littrow 結構

Due to the semiconductor lasers’ small size, high efficiency and relatively low price, they have been widely used in daily life. However, the linewidth of the semiconductor lasers increases with more output power, and the center frequency is susceptible to temperature and injection current, which makes these lasers inconvenient in physical and optical experiments. In order to obtain a narrow linewidth and frequency adjustable laser, we use the Littrow configuration to form an external cavity diode laser (ECDL). In the past, a single longitudinal mode green laser can be obtained by using the intra cavity frequency-doubled design. The diode-pumped solid-state lasers can emit 532 nm green laser, but they are heavy and energy consuming. In recently, the diode lasers based on InGaN compound semiconductors can directly emit green laser and are expected to replace the traditional diode-pumped solid-state laser.
In this thesis, we use the green diode laser as a study. First of all, we used a spectrometer to analyze the changes of laser spectrum under the different operating currents, and measured the wavelength tunable range of ECDL. Then we measured the output characteristics of the laser at different temperatures, and the output efficiency of ECDL under different polarizations. Finally, we obtained the linewidth of ECDL by using scanning Fabry-Perot interferometer.
We have successfully produced a temperature controlled green ECDL, whose wavelength is 518nm and its efficiency is about 52%. At 25oC, the output power is 41.9 mW, and linewidth is about 10.3 MHz under the two times of the threshold current.
Keyword：External cavity diode laser (ECDL), Littrow configuration

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