The research of single-frequency external cavity green laser

  • 林 韋辰

Student thesis: Master's Thesis


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
Date of Award2017 Jul 27
Original languageEnglish
SupervisorHsiang-Chen Chui (Supervisor)

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