Spectroscopic studies of the population of high-energy levels of Nd3+-doped laser crystals upon intense pumping

The luminescence of Nd:YAG and Nd:YAP crystals excited by intense 808-nm radiation from laser diodes and the second (532 nm), third (354.7 nm), and fourth (266 nm) harmonics of a pulsed Nd:YAG laser is studied in the range from 380 to 650 nm. A number of intense luminescence lines are assigned to the transitions from the high ²F(2)_5/2 level. A channel of the efficient population of this level upon simultaneous pumping a Nd:YAG crystal by a diode laser and the second harmonic of the Nd:YAG laser is found.