Evidence of self-frequency doubling from two inequivalent Nd~(3+) centers in the La_2CaB_(10)O_(19):Nd~(3+) bifunctional crystal

摘要

Nd_xLa_(2-x)CaB_(10)O_(19) crystals with different Nd~(3+) concentrations were grown by the high-temperature flux method. Room-temperature spectroscopy, i.e., absorption, emission, and lifetime measurements, was used to obtain the signatures of two inequivalent Nd~(3+) centers in the crystal host. They are attributed to Nd~(3+) substitution of both La~(3+) and Ca~(2+) sites. Nonradiative energy losses were estimated with the help of the Judd-Ofelt analysis. Self-frequency doubling of the ~4F_(3/2)→~4I_(11/2) Nd~(3+) laser channel with 5% efficiency was demonstrated in the XZ principal plane. It is clearly shown that self-frequency doubling can occur from two inequivalent luminescent centers.