Widely Tunable Picosecond Laser Based On Optical Superlattice

The near-infrared and mid-infrared laser is widely used in the atmospheric communication, environmental monitoring, military, medical and other fields. Tunable picosecond laser due to its short pulse width with wide tunable wavelength property, has a great application prospect in the field of spectral analysis, the LIDAR and some other areas. The market needs practical tunable picosecond laser. The optical parametric oscillator(OPO) is an ideal method to produce laser form the near-infrared to mid-infrared. In recent years, many researchers have studied the mid-infrared tunable picosecond laser about more efficient and more wide tuning range under laboratory conditions. In this paper, in order to obtain stable and reliable widely tunable picosecond laser, we studied the tunable picosecond laser form the near-infrared to mid-infrared using the OPO technology based on optical superlattice. We developed the widely tunable picosecond laser which is practical and useful. Since it is hard to obtain high power laser at long wavelength such as 3.8um, we designed a picosecond cascade OPO-OPA process that has greatly improved the conversion efficiency at long wavelength. The main content of this thesis are as follows:1. Using the OPO technology based on optical superlattice, we designed a widely tunable picosecond laser which has compact structure and high environmental adaptability.2. Using a piece of MgO:PPLN crystal which has eight channels, we developed a tunable picosecond laser which can output laser from 1.5um to 4.3um. The highest output power of this laser can reach 5W, and about 1W among all the wavelength. We measured the beam quality and pulse width by building measuring devices all by ourselves. The pulse width of this laser is about 21 picosecond and the beam quality is quite good. This picosecond laser has a great stability. It has operated about 1000 hours without any trouble.3. Using the picosecond cascade OPO-OPA process, we designed the cascade crystal to produce high efficient laser at long wavelength. Usually it is hard to get high efficient or high power laser at long wavelength. We got 2.2W at 3.87um while the pump power was 17.2W. Compared with an ordinary process of OPO, the output power increased by 69.2%. The cascade OPO-OPA process provides a feasible solution to obtain high efficient or high power laser at long wavelength.