报告题目：Frequency References in Blue-Green Region using Laser Diodes
This series of research works aims to develop frequency standards in blue-green region. At first, the longitudinal mode evolution of an InGaN green and blue laser diode was investigated. A spectrometer with a 3-pm resolution was employed to obtain the emission spectra of a green and blue laser diodes(LDs). We presented a design of a single-frequency green InGaN external cavity diode laser (ECDL) with 40-mW output power and 10-MHz linewidth. To my knowledge, it is first to realize green ECDL. We analyzed the output efficiency of the ECDL under different polarization directions and emitted light patterns. The laser spectrum under the different applied currents and temperatures were also investigated. we obtained the information of tuning range and linewidth with applied current. We found that the LD output spectrum showed a nearly single longitudinal mode when the low applied current slightly exceeds the threshold. We fine-tuned LD temperature and current to obtain a 522-nm diode laser that can function as a single-frequency laser with low mW output. This laser has potential applications in spectroscopic analysis.