Growth of a large-aperture mid-infrared nonlinear optical La3Nb0.5Ga5.5O14 crystal for optical parametric chirped-pulse amplification

The optical parametric chirped-pulse amplification (OPCPA) technique is the key for achieving ultrahigh peak power lasers, whose development is hindered by the rare large aperture mid-infrared nonlinear crystals with high damage thresholds. Here, we present the growth and characterization of a La3Nb0.5Ga5.5O14 (LGN) crystal with a diameter up to 60 mm and high optical quality. Its broadband transparency up to 7.4 mu m is attributed to the suppression of the second-order infrared absorption. This work not only provides a promising candidate for the mid-infrared OPCPA system, but also offers a new thought of properly designing nonlinear optical crystals from the perspective of structural properties.