Popis: |
Photorefractive materials for phase conjugation in the ultraviolet are studied. In the canonical understanding the photorefractive effect is due to crystal impurities. With doping of the UV-transparent crystals beta-barium-borate (BBO), lithium-tetra-borate (LTB), and potassium-dihydrogen-phosphate (KDP) with transition metals, photorefractive properties can be achieved. In nominally pure LTB pumped with 150 mW of the 364-nm cw argon-ion laser line, we already observed a phase-conjugate reflectivity of 0.15%. |