Recently, the research team of Sun Dunlu, Anhui Institute of Optics and Mechanics, Institute of Hefei, Chinese Academy of Sciences, has made a series of research progress in the research of 1.06 micron near-infrared and 2.7-3 micron mid-infrared laser crystals.

1.06 micron laser is widely used in processing, medical, communication, display and other fields. Nd3+ doped yttrium aluminum garnet crystal has the advantages of stable physical and chemical properties, high mechanical strength and hardness, and excellent thermal properties, and is suitable for high power laser operation. However, due to the low effective segregation coefficient of Nd3+ in YAG matrix crystals, it is not suitable for high concentration doping. In addition, flash-pumped Nd3+ single-doped YAG crystals have the problem of low laser output energy and low efficiency.

In response to the above problems, Dr. Zhang Huili and others in the research group increased the flash pumping efficiency by co-doping Cr3+ as a sensitizer, and the co-doping of Cr3+ can also improve the radiation resistance of the crystal. High optical quality Cr, Nd:YAG crystals were successfully grown by melt pulling method. At a repetition rate of 40 Hz, the laser output with maximum average output power of 20.24W, electro-optic efficiency of 3.00% and oblique efficiency of 3.77% was achieved. Under the same conditions, the values on the Nd:YAG crystal were only 13.32 W, 1.97%, and 2.47%, respectively. The results show that the laser performance can be effectively improved by incorporating the sensitized ion Cr3+, and the effect on the beam quality is small.

2.7-3 micron mid-infrared lasers are widely used in biomedical, atmospheric detection and scientific research. The research group used Er:YAG and Cr,Er:YAG crystals by the Czochralski method to compare the crystal quality, spectrum, laser performance and beam quality. When the repetition frequency is 5 Hz, the maximum single pulse energy of 1.52 joules, the oblique efficiency of 1.80%, and the electrooptic efficiency of 1.28% of the 2.94 micron mid-infrared laser output are achieved on the Cr, Er:YAG crystal, and under the same conditions, in Er: The values of YAG crystals are only 0.99 joules, 1.31% and 0.83%, respectively. The results show that the co-doped Cr3+ makes the energy and efficiency of the mid-infrared laser output of Cr, Er:YAG crystals greatly improved.

Researchers say the above work is important for improving the performance of 1.06 micron near-infrared and 2.7-3 micron mid-infrared laser crystals and advancing their practical applications. Relevant research results have been published in the academic journalsOptical EngineeringandInfrared Physics & Technology.