UV light irradiation for optical damage control in near-stoichiometric LiNbO/sub 3/

Summary form only given. The electric field required for ferroelectric domain switching in near-stoichiometric LiNbO/sub 3/ (SLN) is decreased to be less than 4 kV/mm, which is about one fifth of the field for congruent conventional LiNbO/sub 3/ (CLN). This low coercive field in SLN has increased the interest in domain engineering for optical devices in a variety of frequency conversion applications. However, the photorefractive damage causing a beam fanning is enhanced in SLN and this poses serious limitation on using this material for UV frequency conversion. In this study, the photovoltaic coefficient (Glass constant) and photoconductivity of SLN have been measured at two different wavelengths (532 nm green and 350 nm UV lights). It has been confirmed that the optical damage hardly occurs under the irradiation of UV light in SLN as well as in near-stoichiometric LT. Using this result, the optical damage caused by 532 mn green laser can be suppressed by the UV light irradiation by superimposing it on the green light path in LN crystal.