Optical crystals surviving in IT systems

摘要

Different optical crystals are reviewed from the viewpoint of their optical properties, among which typical crystals survived in the recent Information Technology (IT) systems. Most of revived or survived crystals are somehow traditional ones, because of their established properties. Potential applications of oxide crystals into shorter wavelengths are focused as additional ripple effects of the impetuous deployment of the IT. Some recent activities on developing new crystals are described briefly; GdVO_4 with a large walk-off angle as a birefringent crystal, Y_2O_3 as a new laser host, periodically poled ferroelectric LiNbO_3 and LiTaO_3 crystals as effective devices of frequency conversion, and traditional sapphire as a potential substrate of GaN-LEDs.