Annealing method for improving laser output power of Nd3+:YAG crystal

Abstract

The invention discloses an annealing method for improving laser output power of Nd3+:YAG crystal. The annealing method comprises the following steps of 1, putting an Nd3+:YAG crystal bar into a vacuum annealing furnace, and vacuumizing the vacuum annealing furnace to 0.08MPa by a vacuum pump; 2, opening an air inflation device, supplying a mixture gas of nitrogen and oxygen into the vacuum annealing furnace by a vacuum pipe, and maintaining the air pressure in the vacuum annealing furnace to 0MPa; 3, after the step 2 is finished, increasing the temperature in the vacuum annealing furnace to 1250-1300 DEG C; 4, maintaining the temperature in the vacuum annealing furnace to 1250-1300 DEG C; 5, after the step 4 is completed, lowering the temperature in the vacuum annealing furnace to 800 DEG C, and naturally cooling to the room temperature along with the furnace. Theannealing method has the advantages that by changing the annealing atmosphere, the constant temperature and the constant-temperature yearly hour are improved, so that the laser output power of the Nd3+:YAG crystal is greatly improved; compared with similar types of existing products, the laser output power is improved by 10-15%.

Description

technical field [0001] The invention relates to the field of laser crystal annealing treatment, in particular to a method for increasing Nd 3+ : The annealing method of YAG crystal laser output power. Background technique [0002] Nd grown by pulling method 3+ : YAG crystal due to Nd 2+ Oxygen vacancies due to the existence of oxygen vacancies, so it is often necessary to perform annealing treatment with oxygen supplementation, that is to say, it is usually necessary to add Nd 3+ : YAG crystals are annealed in the presence of oxygen. In the prior art, annealing under air atmosphere and annealing under pure oxygen atmosphere are generally used, because annealing under air atmosphere has two serious disadvantages: one is that the impurities mixed in the air easily cause secondary pollution to the crystal, and the other is that the annealing temperature is relatively high , the brightness and transmittance of the crystal are not ideal, and the annealing efficiency is not hi...

AI Technical Summary

Problems solved by technology

In the prior art, annealing under air atmosphere and annealing under pure oxygen atmosphere are generally used, because annealing under air atmosphere has two serious disadvantages: one is that the impurities mixed in the air easily cause secondary pollution to the crystal, and the other is that the annealing temperature is relatively high , the brightness and transmittance of the crystal are not ideal, and the annealing efficiency is not high, so the annealing treatment under pure oxygen atmosphere has been widely used.

[0003] However, this method has several important disadvantages: 1. According to the principle of thermal diffusion in air, when the laser crystal is placed in a pure oxygen environment at room temperature, oxygen molecules can hardly diffuse into the crystal due to the small kinetic energy of oxygen molecules , as the temperature rises, the oxygen molecules gain more and more kinetic energy, and then thermal diffusion occurs. When the temperature reaches a certain critical value, the oxygen molecules begin to gradually diffuse into the laser crystal. As the temperature continues to rise, The diffusion speed of oxygen molecules is getting faster and faster until it reaches a certain dynamic equilibrium (related to the form of matter, such as solid and liquid), and the speed of oxygen supplementation is the best at this time

Therefore, improving the effect of supplementing oxygen through the intake of oxygen will cause a large amount of oxygen to be wasted. At the same time, excessive use of oxygen will also lead to more severe oxidation of parts such as pipe plugs, which will adversely affect the use and maintenance of equipment; 2. Since constant temperature and time are the decisive factors for the effect of oxygen supplementation, the choice of constant temperature temperature is particularly important. If the temperature is too low, the diffusion of oxygen molecules will be slow, the constant temperature time will become longer, and the temperature will be too high. Structure, after the constant temperature is determined, the length of the constant temperature time directly affects the effect of oxygen supplementation. In Example 1 of this patent, the constant temperature time is 1200 ° C. It is measured through experiments that Nd 3+ : Oxygen supplementation of YAG crystal is not sufficient, and the oxygen supplementation effect is not ideal. Obviously, this patent does not take into account the importance of the constant temperature time on the oxygen supplementation effect; 3. The cycle of the annealing process is relatively long, and the heating rate is the highest at 70 °C / h, the highest cooling rate is 70 °C / h, and the cooling temperature is below 200 °C, which obviously increases the heating time and cooling time, which not only affects the annealing efficiency, but also causes a certain waste of resources