We report studies of photochromic damage induced in KTiOPO4 single crystals by ultraviolet (UV) irradiation with peak intensities from 0.3 to 4.0 MW/cm2. The photochromic damage progressed to asymptotic values which were not linear with respect to UV intensity. Following UV exposure, transparency of damaged crystals recovered completely over tens of hours at room temperature, faster at elevated temperature. UV irradiation at significantly lower peak but higher average power did not produce damage. We also studied photochromic damage occurring during 1.064‐μm second‐harmonic generation. Fundamental infrared intensities ranged from 1.3 to 5.5 times larger than those producing highest nonlinear frequency conversion efficiency. Damage sites produced by the two methods exhibited similar absorption spectra.
[1]
D. Eimerl,et al.
High average power harmonic generation
,
1987
.
[2]
E. Teppo,et al.
Bulk-darkening threshold of flux-grown KTiOPO(4).
,
1991,
Optics letters.
[3]
G. Loiacono,et al.
Laser damage formation in KTiOPO4 and KTiOAsO4 crystals: Grey tracks
,
1992
.
[4]
G. Loiacono,et al.
Growth of large single crystals of KTiOPO4 (KTP) from high-temperature solution using heat pipe based furnace system
,
1987
.
[5]
Jacek K. Tyminski.
Photorefractive damage in KTP used as second-harmonic generator
,
1991
.