Self-pumped phase conjugation in the red in photorefractive Ba_05Sr_15K_025Na_075Nb_5O_15 and Sr_06Ba_04Nb_2O_6 with cerium in 9-fold coordinated sites

Abstract

Self-pumped phase conjugation has been observed at selected laser wavelengths over the range 647–780 nm. Phase-conjugate reflectivities as great as 20% were measured for power levels ranging from 2 to 100 mW. In addition, phase-conjugate and beam-fanning response times were also measured. Our observations were carried out in crystals belonging to the tungsten-bronze family; these crystals were doped with cerium at the 9-fold coordinated lattice sites to give a red photorefractive response.