High-power broadly tunable grating-coupled external cavity laser in green region

• Published in: Review of scientific instruments 2018-12, Vol.89 (12), p.125106-125106
• Main Authors: Xu, Binbin, Lv, Xueqin, Ding, Ding, Lv, Wenlong, Zhang, Yan, Zhang, Jiangyong
• Format: Article
• Language: English
• Subjects: Clean energy; Diffraction efficiency; Efficiency; External-cavity lasers; Gratings (spectra); Lasers; Light diffraction; Modal choice; Scientific apparatus & instruments; Second harmonic generation; Semiconductor lasers; Tunable lasers; Tuning
• ISSN: 0034-6748; 1089-7623
• DOI: 10.1063/1.5048977

A broadly tunable grating-coupled external cavity laser system in the green region is demonstrated by employing a commercially available broad-area green laser diode. A simple Littrow-type external cavity configuration was adopted, and two gratings with different diffraction efficiencies were used as the light feedback elements. When a grating with the first-order diffraction efficiency of 50% and the zeroth-order diffraction efficiency of 31% was used, a tuning bandwidth of 11.0 nm with an output power near 400 mW was achieved. When a grating with the first-order diffraction efficiency of 10% and the zeroth-order diffraction efficiency of 78% was used, a tuning bandwidth of 5.0 nm with an output power near 750 mW was achieved. Meanwhile, the spectral linewidth was narrowed significantly down to 0.08-0.18 nm from the free-running linewidth of 2.81 nm due to the external mode selection effect. Such high-power broadly tunable green EC lasers are important for second harmonic generation.