Growth, Characterization and Non‐Critical Phase‐Matching of Niobium‐Doped KTP Crystals

A series of niobium doped KTP (Nb: KTP) crystals has been grown. XRD and DTA experiments show that the Nb: KTP crystal structures do not differ from that of KTP (within experimental error) and that the melting points of the crystals increase with increasing Nb content. Synchrotron radiation topography revealed that the main defects of the crystals were growth sector boundaries, growth striations, inclusions and dislocations. Second harmonic generation experiments were performed using a 12.2% Nb:KTP and the d15and d24values of csystal were determined to be (3.7 ± 0.4) and (8.3 ± 0.8) × 10−9esu, respectively. The relationship between phase‐matching angle and Nb content for a 1.064 μm laser was determined and in the case of a 4.0% Nb:KTP crystal, non‐critical phase matching was realized.