Recently, Jiang Haihe, a researcher at the Center for Medical Physics and Technology of Hefei Institute of Material Science, Chinese Academy of Sciences, made progress in the study of wide-tunable and narrow-spectrum mid-infrared light parameters.
3-5μm mid-infrared laser is widely used in atmospheric environment monitoring, target feature detection and high-resolution spectroscopy, and narrow linewidth tunable laser is the ideal light source for such applications. Optical parametric oscillation (OPO) is However, in the general case, the output of the free-running OPO pulsed mid-infrared laser has a wide spectral range, usually up to tens of nanometers and even hundreds of nanometers, which severely limits the OPO mid-infrared light source .In order to reduce the output spectral width of OPO, it is usually to use cavity insertion etalon or VBG and other frequency selective components.However, this method introduces larger extra loss, which not only leads to the increase of OPO oscillation threshold, but also reduces the mid-infrared laser Of the conversion efficiency; the use of VBG frequency selective components will also severely limit the OPO wavelength tuning range.Therefore, wide-tuned, narrow spectral width efficient OPO laser has become the focus of the research of mid-infrared laser technology.
Based on this, Jianghai River's research team first obtained PPMgLN-OPO with a single longitudinal mode pulsed fiber laser to obtain a high-efficiency mid-infrared laser output. Using the etalon design as the OPO cavity mirror, the gain spectrum of the oscillating signal light Wide modulation and control; At the same time, the use of seed self-injection technology and double solid etalon coupling cavity, the weak side of the oscillation signal light has been further suppressed, to achieve a narrow spectral width of the signal light oscillation, and with the single cavity Longitudinal mode pump light to obtain the output of narrow-band-width OPO mid-infrared laser.In the experimental results, the spectrum width of idler light is narrow to 0.36nm, Improved about two orders of magnitude, and its wavelength tuning range of 200nm, the maximum output power of 2.6W, the corresponding optical conversion efficiency of 17.4%, as the narrow band width of the most effective technical methods used in this study The phase-locked polarizer crystal MgO: PPLN has the advantages of high gain and wide tuning. The 1μm fiber laser with pump source has high stability and compactness. The OPO mid-infrared laser output has high Value of the power, low threshold, wide tunable, narrow spectral width infrared laser OPO efficient application basis.
Relevant research results published in the optical journal OpticsExpress.This research has been funded by the National Natural Science Foundation of China, CASS strategic pilot science and technology projects such as funding.
