Laser crystals doped with holmium, chromium, erbium, thulium and yttrium aluminum garnet, and preparation method thereof

Abstract

The invention discloses Ho:Cr:Er:Tm:YAG-doped laser crystals and a preparation method thereof. The chemical composition of the laser crystal is Ho[a]Tm[b]Er[c]Y[3-a-b-c]Cr[d]Al[5-d]O[12], wherein a is more than 0.003, and less than or equal to 0.018; b is more than or equal to 0.06, and less than or equal to 0.30, c is more than 0, and less than or equal to 1.5; and d is more than 0, and less than or equal to 0.25. The method for preparing the Ho:Cr:Er:Tm:YAG-doped laser crystals comprises the following steps: (1) placing desiccant in a crystal growth furnace to absorb moisture in an atmosphere in the furnace; (2) vacuumizing the crystal growth furnace and performing continuous baking for 8 to 12 hours at a temperature of between 200 and 500 DEG C when the pressure in the furnace is not greater than 5*10 Pa so as to remove the moisture in the furnace; (3) filling the furnace with argon gas or nitrogen of which the water content is not higher than 1.5 ppm; and (4) treating Ho:Cr:Er:Tm:YAG-doped crystals grown in an inert atmosphere in a muffle furnace for 15 to 20 hours at a high temperature of 1,300 DEG C. The preparation method can further improve the rate of Ho-doped crystals in absorbing and utilizing flashlamp pumped energy, and has the advantages of improving the optical quality and optical homogeneity of the crystals, reducing the thermal effect of pumping, reducing laser loss, reducing pumping threshold and improving laser efficiency.

Description

technical field [0001] The invention relates to a laser crystal and a preparation method thereof, in particular to a laser crystal doped with holmium, chromium, erbium and thulium yttrium aluminum garnet and a preparation method thereof. Background technique [0002] The holmium (Ho) laser with a wavelength of 2.1 μm can be strongly absorbed by human tissues and has a shallow penetration depth. Therefore, it is used in laser surgery with little damage to human tissues and has ideal resection, vaporization, ablation and coagulation effects. Moreover, the precision of surgical control is high, and it is especially suitable for surgery on lesions with dense nerves and blood vessels. Ho laser can be used in anhydrous (low OH - Ion content) silica optical fiber transmission, low transmission loss, high efficiency, easy to make an efficient optical fiber transmission laser medical system. Therefore, the Ho laser surgical treatment instrument has been widely used in human body su...

AI Technical Summary

Problems solved by technology

However, Ho:Cr:Tm:YAG crystals reflect some obvious deficiencies in the use of lasers, for example, under the usual pump input power or energy conditions, the obtained laser output power or energy is low; When the output power or energy decreases, the beam quality deteriorates, or even the crystal is damaged or destroyed when working with high-power laser input or high repetition frequency; in order to obtain high-power laser output, double crystal rods or multiple crystal rods have to be used The method of combined output, such as the 60W Ho laser surgical treatment instrument manufactured by Coherent, has to use 4 Cr:Tm:Ho:YAG crystal rods for combined output, and each rod outputs 15W, which is very inconvenient to use

The main reasons for the above problems are due to the high pumping threshold of the crystal, the low laser efficiency and the serious pumping thermal effect.

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