Studies On The Mid-infrared Optical Parametric Oscillator

Mid-infrared lasers have an extremely important value and promising future in the fields of scientific research, military and civilian. Optical parametric oscillator is one of the most effective means of obtaining the mid-infrared laser. Designing a high-quality optical parametric oscillator plays a very important role for future social development. In this study, mid-infrared optical parametric oscillator based on MgO:PPLN is studied on the basis of theoretical analysis.Theoretically, this article analyzed the characteristics of the optical parametric oscillator technology, made an introduction of the basic principles for the optical parametric oscillator, especially the phase matching technology. Then we analyzed some theoretical properties of optical parametric oscillation, including gain and thresholds and conversion efficiency of the OPO.Experimentally, a new laser system is investigated as a pump source of CW Mid-IR OPO. A single-frequency CW seed source is amplified by a fiber amplifier and then by a two-stage solid-state laser amplifier. The maximum output power of the system is 31.9W. The M2 factor is less than 1.5. The experimental results verified that the combined amplifier with both fiber amplifier and solid-state laser amplifier is an effective way to achieve power amplification. And it provided a high quality pump sources for the study of the subsequent mid-infrared optical parametric oscillator technology.An external-cavity CW optical parametric oscillator based on PPMgOLN crystal is studied in this thesis. Through the research of the periodic tuning and temperature tuning of PPMgOLN crystal, the feasibility of the use of PPMgOLN to achieve 2.9μm mid-infrared laser has been verified and the tuning mode is determined to use the temperature tuning. Comparing the output characters of OPO with different parameters, including the reflectivity and the radius of the output mirror and the cavity length, we optimized the cavity parameters. And finally we obtained the output power of 5.2W of 2.9μm idler laser when the pump power is 31.9W.