B. G. Malinin

A kilowatt, two-waveguide slab laser

Construction principles and an optical layout have been developed for solid-state diode-pumped lasers based on a two-waveguide slab active element with conductive cooling that allows scaling of the power in the kilowatt range. Prototypes of a two-waveguide diode-pumped Nd:YAG laser with a mean radiation power of up to 1000 W have been investigated. The possibility is discussed of using slab elements made from heat-strengthened neodymium glass to create powerful pulsed-periodic slab lasers.

High-average-power double-waveguide slab laser for material processing

Novel principles of design of a diode-pumped solid-state laser with scalable average output power are described. The approach is based on a double waveguide slab (DWS) concept, when laser slab has a waveguide equality both for pump and laser radiation propagation in the orthogonal directions. The advantages of such a scheme are efficient conduction- cooling and scalability of a laser head to the kW range with the high quality of a laser beam. The feasibility of this concept was proved with the model of a DWS Nd:YAG laser at the level of average output power of 10W. The promising possibility to use thermally strengthened Nd-glass for a high average power qcw laser is discussed.

Multiwavelength YAG:Nd/Ho laser surgery setups

Elaboration and application to clinical practice of new laser technologies, based on use of high intensity radiation, provided by IR solid-state lasers on the crystals YAG:Nd (1.06 mm and 1.32 mm) and YAG:Ho (2.09 mm), whose surgery action is different, is one of the most important fields of laser surgery. Our experiments, which were carried out on animals, have shown that the treatment methods, based on the use of radiation of these lasers provide the best covering of surgery (general and endoscopic) necessities. The reasons are as follows. On the one hand, one has the possibility to organize loss-free transport of radiation of YAG:Nd/Ho lasers via the fused silica fiber optical waveguide to practically any place in the patients body. On the other hand, various ranges of penetration depths -- from much less than 1 mm to 1 cm -- provides variety of surgery effects. The action of these lasers emission onto the surgery field is well controllable and differential and thus makes it possible to vary its effect just in the course of operation.

Application of IR, YAG:Nd, and YAG:Ho lasers in clinical pulmonology

Involving high-power lasers into clinic medicine significantly extended the possibilities of the endoscopic surgery, which in a number of cases becomes a serious competitor to the traditional surgical methods of treatment1,2 Endoscopic surgeiy lowers the intervention risk, reduces the terms of patients hospital treatment, the patient s activity can be restored in a shorter post-operational period and a possibility appears of carrying out complex operatirns in ambulance conditions. Endoscopic operations nowadays are made using mostly a continuous YAG: Nd laser with operating wavelength 1.06 tm. However, there exist serious restrictions on use of this type of radiation for the endoscopic surgical interventions at the gastrointestinal organs. They are connected with wall perforation risk . Endoscopic using of a cO-laser, which works as an excellent scalpel in general surgety, is connected with technical difficulties of 10.6 jim radiation transmission by a flexible light guide. Moreover, the the hemostatic properties of this kind of radiation are rather limited. The specified above reasons stipulated that the practical medicine be interested in solid YAG-cr-Tm: Ho lasers with wavelength range of 2 im and their application in the endoscopic surgeiy. This report consists of two parts: experimental and clinical ones. The experimental data presents the character of pulse-repetitive YAG:Nd and YAG:cr,Tm,Ho lasers radiation action in comparison with the radiation from cwYAG:Ndlaser. The second part presents the results ofthose lasers application to endobronchial surgery.

10-W Ho laser for surgery

Practical use of laser tecnique surgery demonstrated the true choice of lasers generating in the long wavelength spectrum. In this field the pigment content of biologic tissues is not noted at absorption spectrum. The latter is generally defined by the percentage of water in tissues. Among the known laser types the most proved and developed are the lasers generating at 1060 nm, 2090 nra, 2900 nii and 10600 nm. Ho-lasers of 2090 nm radia tion wavelength are perspective instruments for surgery purposes due to the high radiation absorption at biologic tissues: 30 cru This value is much higher than the absoptance at 1060 mit and a little bit lower at 1060 nm. An important feature that distinguishes Ho-laser among other types is the possibility of its use with fiber channel made of fused silica for abdominal operations.