Two-photon absorption in La0.05Gd0.95VO4 crystal at 523 nm under irradiation with picosecond pulses

Abstract

Abstract Two-photon absorption (TPA) in La0.05Gd0.95VO4 crystal under irradiation with picosecond laser pulses with the duration of 25 ps at the wavelength of 523.5 nm has been investigated. The TPA coefficient was measured to be 0.074 cm/GW. We found that the two-photon inter-band excitation led to the creation of optical centers, which were characterized by a wide absorption band in the visible spectral region. The decay of the induced absorption is characterized by two temporal stages. The first rapid stage has the decay time of about 70 μs. However, the slow stage is characterized by a decay time ranging from 270 to 520 ms depending on the initial concentration of the induced optical centers. Induced absorption should be taken into account when developing vanadate lasers with intra-cavity second harmonic converters.