Growth of NdxGd1-xCa4O(BO3)(3) along phase-matching direction and passive mode-locking self-frequency-doubling characteristics

NdxGd1-xCa4O(BO3)(3) (NdGdCOB) grown along the optimum phase-matching (PM) direction (theta=66.8 degrees, Phi = 132.6 degrees) is reported for the fir st time in this paper. The utilization ratio of the as-grown crystals along the optimum PM direction is improved up to 95% when the optical devices we re processed, while it is only 50% for the crystals grown along [0 1 0] dir ection. It often shows two large (1 5 0) facets and growth edge facets on t he as-grown crystal surface. The small facets on the shoulders were determi ned as ((2) over bar 0 1) facets by X-rays. The ((2) over bar 0 1) edge fac ets will vanish and (0 1 0) edge facets will emerge when the crystal is tap ered. The (0 1 0) edge facets which anchor at the three-phase-boundary (TPB ) are the principal cause for the formation of (0 1 0) twins. Passive modul ated Q-switched and mode-locking green laser operation at 530 nm were achie ved in NdGdCOB crystal using a xenon flash lamp as the pump source, Cr4+ : YAG crystal as the saturable absorber with a plane-concave cavity, which is also reported here for the first time. (C) 2000 Elsevier Science B.V. All rights reserved.