The purpose of this project is to build an external-cavity diode laser from a commercial 808nm diode laser. External-cavity diode lasers (ECDLs) are laser sources with many applications where a tunable and narrow line-width light source is required. Such as spectroscopy, optical components characterization, and telecommunication. As a tunable laser source, though ECDLs are known for its sensitivity to misalignment and can be easily influenced by environment, they are simpler to build, compared to other tunable lasers like Distributed Bragg Reflector Lasers. This project is just a small part of a big plan. The long-term goal is to construct a chirped Terahertz source, and this ECDL is a piece of it. In this report, we present Littrow and Littman-Metcalf configuration, and we successfully demonstrated wavelength tuning in the latter one.

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First, I appreciate all the help and effort from Prof. Yen-Chieh Huang. He always shows kindness and patience helping me, also showing the right way to learn and to do research. Second, I would like to thank all the members in HopeLab, especially Yu-Chung Chiu, Meng-Wei Lin, and Zhao Gang. They helped me a lot on this project and build the knowledge and skills. Without them I would not be able to finish this project.