​Laser characteristics of sapphire crystal (5)

Laser characteristics of sapphire crystal (5)

During RE cao operation, the individual lesion areas are similar in size to the accumulation of pores in the body. Their number grows to tens of per cubic centimeter over time. The star-shaped area of injury is as long as tens of millimeters, while the trajectory type HKUST tens of centimeters. However, the total damage volume will not exceed 1-8% of the component volume. Except for the volume generated by the resulting volume, there will be no significant changes in pulse energy or radiation direction. Even with many damaged areas The originals can withstand hundreds or thousands of pulses. If they overlap a substantial portion of the RE intersection, a large damage area at the end face and in the body is detrimental. Surface and bulk strength test data for ruby and sapphire obtained in the single-mode generation protocol are listed in Table 2.15.

Radiation resistance of rubies. CC equilibrium numbers are even observed in unirradiated rubies. The radiation resistance of RE is characterized by changes in pulse energy (Ep) and threshold energy (Et) (Tables 2.16-2.18). There is a correlation between the generation parameters and the overall deformation of the EPR spectra (parameters β are listed in Tables 2.17 and 2.18). The stretching of the presented data is related to the amount of impurities in the RE and other individual properties of the crystal.

The valence transition of impurity ions leads to changes in the parameters of the laser radiation during the emission process. The reduction of the number of emitted ions and the change of the energy movement and dispersion process.

The probability of changing the number of dopant electrons during emission depends on the ratio of the electron ionization (capture) energy to the Madelung constant αM. If the ionization energy is higher than the absolute amount of αM, then the electronic state (IMe+n) is stable [96]:

IMe + n > |αM| (2.10)

In this formula, the lattice distortion caused by the impurity ions is not taken into account. For the ideal sapphire cation site, αM = -35.2 eV and the potential energy IMe of the Al ion has the following values: IAl+=18.83 eV; IAl2+=28.45 eV; [ 97] and IAl3+=119.98 eV. The difference of IAl3+-|αM|=84.8 eV indicates the high temperature characterization of Al3+ state in corundum. For impurity ions, ICr2+=33.2; ICr3+=52; IFe2+=30.6; IFe3+=57.1 and IMn2+ =34 eV.

The formation of charge-deficient or charge-excess cations in the second coordination sphere does not change the valence state of the impurity. Therefore, the Mn2+-Mn4+ pair does not form in the ideal lattice of sapphire. The appearance of an electronic state that does not satisfy relation (II9) indicates that A large number of defects stabilize this state.

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