Dependence of photochromic damage on polarization in KTiOPO4 crystals

Studies of photochromic damage induced in KTiOPO4 single crystals by 514.5 nm laser irradiation is reported. A dependence of photochromic damage on polarization was observed. Along the same propagation direction (<f>θ=90°</f>, <f>ϕ=23.3°</f>), the gray-track susceptibility for <f>&par;z</f> polarization irradiation is one order magnitude lower than that for <f>⊥z</f> polarization irradiation for KTP crystal. The results clearly show that in KTiOPO4, a correlation exists between the gray-track susceptibility and the ionic electrical conductivity. Due to a high ionic electrical conductivity along the polar z-axis, the optical absorption centers will be annihilated with <f>&par;z</f> polarization irradiation as soon as they are produced. This results in a lower gray-track susceptibility for <f>&par;z</f> polarization irradiation. [Copyright &y& Elsevier]