RECENT DEVELOPMENTS IN THE GROWTH AND CHARACTERIZATION OF POTASSIUM LITHIUM-NIOBATE (KLN) CRYSTALS FOR DIRECT DOUBLING OF SEMICONDUCTOR-LASERS

This paper reports the successful growth of crystals of the potassium lithium niobate (KLN) family having a non-centred tungsten bronze stru cture. Crack free crystals up to 20 mm in diameter by 30 mm in length have been grown reproducibly by the top-seeded solution growth (TSSG) method from K+ and Li+ rich solutions. These crystals form solid solut ions in which both the structural and optical properties vary with com position. Birefringence measurements show that KLN crystals may be non -critically phase matched for second harmonic generation in the wavele ngth range 1050 nm to 820 nm at room temperature, depending on composi tion. The ability to tune the optical properties in this way makes KLN an ideal candidate for direct doubling of semiconductor lasers. (C) 1 998 Chapman & Hall.