PbGa2S4Dy3+

Each type of visual aid has pros and cons that must be evaluated to ensure it will be beneficial to the overall presentation. Before incorporating visual aids into speeches, the speaker should understand that if used incorrectly, the visual will not be an aid, but a distraction.

Planning ahead is important when using visual aids. It is necessary to choose a visual aid that is appropriate for the material and audience. The purpose of the visual aid is to enhance the presentation. Each type of visual aid has pros and cons that must be evaluated to ensure it will be beneficial to the overall presentation. Before incorporating visual aids into speeches, the speaker should understand that if used incorrectly, the visual will not be an aid, but a distraction. Planning ahead is important when using visual aids. It is necessary to choose a visual aid that is appropriate for the material and audience. The purpose of the visual aid is to enhance the presentation.

Generation was obtained at two transitions of the ion Dy^{3+ 6}H_11/2 — ⁶H_13/2 и ⁶H_9/2 — ⁶H_11/2 according to a cascade scheme.
The pumping was carried out with an IAG-Nd3+ laser at a wavelength of 1.38 microns. Measurement of the lifetime of levels ⁶H_9/2, ⁶H_11/2 and ⁶H_13/2 showed that it is equal to 160 microseconds, 2 ms and 5.6 ms. This means that the ⁶H_11/2 — ⁶H_13/2 and ⁶H_9/2 — ⁶H_11/2 laser junctions are self-limited. Generation develops first at the ⁶H_11/2 — ⁶H_13/2 transition, and then with increasing pumping energy at the ⁶H_9/2 — ⁶H_11/2 transition.
The figures showing the luminescence and generation spectra show that generation is achieved simultaneously on six lines.: three in the range of 4.38–4.7 microns and three in the range of 5.2–5.5 microns.
A pulsed and continuous generation mode is obtained. The pulse energy was 30 MJ with a differential efficiency of 8%. The duration of the generation pulses reached 1.5 ms. A prototype of a medium-IR laser with generation from 4.38–5.5 microns on a PbGa2S4 crystal activated by dysprosium ions.
The PbGa2S4:Dy3+ laser material was highly appreciated by the world scientific community, was noted in the article Fifty years of advances in solid-state laser materials, G. Boulon, Optical materials 34 (2012), 499-512, and was among the world's best achievements.

Together with the staff of the Medical University, we investigated the dynamics of the microbicidal activity of neutrophil granulocytes in animals with soft tissue wounds using the created prototype of laser radiation.
All the animals were divided into three groups. The first group was a control group. In the second group of animals, the wound surface was irradiated with a laser for 4 minutes daily with an interval of 24 hours for 14 days (Picture 15 a. b). In the third group, under the same conditions, the duration of exposure was 6 minutes.
The material was collected before the start of the experiment, as well as on the 1st, 4th, 7th and 14th days. Blood smears and exudate prints were stained for Pigarevsky cationic protein, and myeloperoxidase activity was determined by Sat. It was found that during the natural course of the wound process, complete repair did not occur in the rats of the control group by the 17th day of the experiment, as evidenced by the presence of visually detectable skin defects (picture c, d). Irradiation of an experimental rat soft tissue wound for 4 or 6 minutes over 8 days has a pronounced activating effect on the oxygen-dependent and oxygen-independent microbicidal systems of neutrophil granulocytes (NG), which leads to a multiple acceleration of reparative processes in the wound (Picture 15 a, b). The area of the rat wound during the natural healing process decreased by 17 days 8.5%, and when irradiated with a laser for 8 days — by 76.5%. Given the time difference during these experiments, it can be argued that the healing rate when wounds are irradiated with a medium-IR laser is 20 times faster than the rate of the natural healing process.

It is of interest in the future to irradiate rat wounds not for 4 or 6 minutes per day, but for a longer time, up to a continuous radiation regime. Increasing the duration of exposure to wounds with medium infrared radiation may further accelerate their healing.
After additional research, this method can be used in various fields of medicine: disaster medicine, military medicine (in mobile or hospital settings), etc., when rapid and effective wound treatment is of paramount importance for preserving the patient's life and health.
In 2016, the laser on the PbGa2S4:Du3+ element was improved. Generation was obtained at three more wavelengths — 2.4, 4.3 and 5.4 microns. These results appeared in the study of other energy transitions in the laser-active PbGa2S4:Dy3+ material associated with the energy levels ⁶Н_9/2 + ⁶F_11/2 or ⁶Н_11/2. A PbGa2S4:Dy3+-based laser was pumped by radiation from an unsynchronized Nd:YAG laser or by radiation from a laser diode corresponding to the absorption peak of PbGa2S4:Dy3+. The PbGa2S4:Dy3+ crystal was placed in a stable optical resonator with mirrors selected according to the required generation wavelength.