This book contains most, but regrettably not all, the papers that were presented at The Advanced Research Workshop, held July 1-5, 1997, at Smolenice Castle, Slovak Republic. The problem of angular divergence is of great importance in quantum electronics: low divergence is required not only in most of practical laser applications, but also for achieving high efficiency of parametric laser frequency conversion, and harmonic generation. The large volume of available studies aimed at improving the pump systems and the spectroscopic properties of lasing media, brought about no more than 2-3 fold increases in laser efficiency, while concurrent studies of angular divergence and the implementation of the findings, resulted in several order of magnitude of increases in radiance. The spatial beam structure that is formed in the laser cavity together with the active element constitute the most critical laser elements. The engineering devices, such as excitation systems, lasing gas circulation systems, etc., are usually at the top of the agenda of scientific meetings and of gatherings of engineering experts. The divergence problem has never been discussed by a broad community of experts in this field.

Zusammenfassung
Proceedings of the NATO Advanced Research Workshop on Optical Resonators - Theory and Design, Smolenice Castle, Slovak Republic, July 1-5, 1997

Inhalt
Theory of Laser Resonators and of the Beam Divergence.- Laser Resonator Theory.- Nonorthogonal Optical Modes and Resonators.- Influence of Intra-Cavity Distortions on Output of Unstable Resonators.- Optical Resonators with Dielectric Body.- Thermal Lensing in Kerr-Lens Modelocked Solid-State Lasers.- Phase Conjugation Techniques.- Phase Conjugationof CO2 Laser Radiation And Its applications.- Conjugated Cavity With the Wide Field of Vision.- Beam Quality and Efficiency of Annular Gain Lasers.- Unstable Resonators for Semiconductor Lasers.- Chemical Lasers with Annular Gain Media.- Beam Quality Control of an Iodine Laser With SBS.- Flattened Gaussian Beams With Rectangular Symmetry.- Beam Divergency Studies on a Long Pulse XeCI Excimer Laser.- Optical Resonators For a Slab-Waveguide Lasers.- Investigations of Open Resonators With Diffraction Coupling.- Enhancement of Small-Scale Optical Nonuniformities In Active Medium of High-Power CW FAF CO2 laser.- Synthesis of Interferograms by Lateral Shear To Measure Wave Front from a Light Beam.- Resonators For Lasers Used in Precision Technological Operations.- Resonator Design Considerations For Efficient Operation of Solid-State Lasers End-Pumped By High-Power Diod-Bars.- Heterogeneity Structure of Active Medium Refraction For Three-Dimensional Pre-Mixing and Mixing Nozzle Banks of Gasdynamic Laser.- Optimized Resonators for High Energy Long-Pulse Nd:YAG Laser.- High Power Diffraction Limited Solid-State Lasrs With Stable Resonators.- Highly Efficient High-Average Power Nd:YAG Laser With a Passive Q-Switch.- Planar waveguide Lasers of Ti:Sapphire and Nd:YAG (YAP) Grown by LPD.- Problems of CW Chemical Lasers Scaling.- Creation of Channels Into Ti:Sapphire Waveguiding Layers.- Properties of the Cavities for Compact Slab Gas Lasers.- Nd:YAG Laser Resonators Using External Stimulated Brillouin Scattering Q-Switching Mirror.- The Construction of Laser Gyroscope.- SBS Propertis of High-Pressure Xenon at a Density of 0.31 g/cm3.- New Optical Scheme of Complicated Resonator in a Two-Frequency NH3-CO2 Lidar.- List of Participants.