Preparation process of power laser single crystal slabs based on ytterbium-doped garnet aluminates with ASE suppression

摘要

In the present invention, there is disclosed a preparation process of power laser single crystal slabs with the diameter of the active medium of at least 70 mm, based on single crystals of ytterbium-doped garnet aluminates grown onto an oriented nucleus by drawing from a melt in a reducing atmosphere underneath a lid, wherein the preparation process is characterized in that the reducing atmosphere above the melt (10) in a crucible (1) containing during melting at least 30 percent by volume hydrogen is subsequently evacuated, and the melt (10) is homogenized and deprived of dissolved gases by wire agitation (7), whereby thereafter vacuum is again replaced by the reducing atmosphere in order to start growing the garnet on the nucleus, whereupon after the single crystal required site is achieved, the single crystal is further processed by usual mechanical means to a half-finished product for the manufacture of laser slabs, whereby the said half-finished product is subsequently kept at high temperature of at least 200 degC below the melting temperature in a protecting atmosphere of oxygen or nitrogen or air to remove dislocations and conversions of active laser ions. Subsequently it is provided with an absorption layer containing physically and/or chemically created absorption centers for suppressing the phenomenon of an Amplified Spontaneous Emission (ASE), which centers are generated directly in the single crystal material and/or they are formed by a dopant in the added single crystal material through coupling with the half-finished product of the laser slab by high-temperature soldering of the surface layer recrystallization, whereby optical interface of this absorption layer along with the lasering portion of the single crystal is indistinguishable from the refraction index of that absorption layer and material thermal expansion dilatation point of view, whereupon a worked laser slab with surface parameters corresponding to demands made on a laser element id produced from the above-indicated half-finished product for the manufacture of laser slabs.