| Abstract [eng] |
The early development of 2-micron lasers during the period of 1962-1991 was reviewed. At that time, the effective YLF and YAG matrices doped with holmium and thulium ions where introduced. In 1980’s emerged diode pumping increased the efficiency of 2-micron lasers. Passive Q-switched 2-micron laser evolution during the period of 1993-2019 was reviewed. The available laser parameters of pulse duration, energy, frequency and efficiency have been compared. 2-micron laser application in fields of wind speed measurement, vibrometry, medicine and LIDAR’s were reviewed. The principles of passive quality switching are presented. Absorption and emission spectra in Tm: YLF crystal are also provided. During this work, the Tm: YLF laser scheme was constructed. It was tested in both quasi free-running and passive Q-switching modes. Cr: ZnSe absorber was used for Q-switching. Thermal lens in Tm:YLF was estimated. In quasi-free-running mode, 46 mJ of energy pulses were obtained at 5 Hz pumping rate. The laser beam profile and spectrum were measured. The laser polarization was investigated. In passive Q-switching mode, pulses of 0.85 mJ energy and tens of nanosecond length were obtained. Laser worked at 1 Hz repetition rate. The energy was achieved by optimizing the pumping diode current, pumping pulse duration and absorber position in the resonator. |
