PURPOSE: To obtain a lithium tantalate single crystal which has low laser beam absorptivity and therefore is considered as a useful laser beam higher harmonic generating material and also to provide its production method.
CONSTITUTION: The lithium tantalate single crystal contains ≤1ppm each of iridium and rhodium in it. In this production method of the single crystal, lithium tantalate is pulled up by the Czochralski method using a crucible provided with an after-heater. Further, a noble metal contg. no rhodium, e.g. iridium is used as the material for all the parts e.g. the crucible, after-heater, after- heater cover and seed holder that are heated to the temp., at which rhodium is volatilized.
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