Abstract: Provided is a nonlinear optical device manufactured with 4H silicon carbide crystal. The nonlinear optical crystal may be configured to alter at least a light beam (12) at a frequency to generate at least a light beam (16) at a further frequency different from the frequency. The nonlinear optical crystal comprises a 4H silicon carbide crystal (13). The nonlinear optical device is more compatible with practical applications in terms of outputting mid-infrared laser at high power and high quality and thus are more applicable in practice, because the 4H silicon carbide crystal has a relatively high laser induced damage threshold, a relatively broad transmissive band (0.38-5.9 ?m and 6.6-7.08 ?m), a relatively great 2nd-order nonlinear optical coefficient (d15=6.7 pm/V), a relatively great birefringence, a high thermal conductivity (490 Wm?1K?1), and a high chemical stability.

Abstract: A technology for growing silicon carbide single crystals by PVT (Physical Vapor Transport) and a technology for in-situ annealing the crystals after growth is finished is provided. The technology can achieve real-time dynamic control of the temperature distribution of growth chamber by regulating the position of the insulation layer on the upper part of the graphite crucible, thus controlling the temperature distribution of growth chamber in real-time during the growth process according to the needs of the technology, which helps to significantly improve the crystal quality and production yield.

Abstract: Provided is a nonlinear optical device manufactured with 4H silicon carbide crystal. The nonlinear optical crystal may be configured to alter at least a light beam (12) at a frequency to generate at least a light beam (16) at a further frequency different from the frequency. The nonlinear optical crystal comprises a 4H silicon carbide crystal (13). The nonlinear optical device is more compatible with practical applications in terms of outputting mid-infrared laser at high power and high quality and thus are more applicable in practice, because the 4H silicon carbide crystal has a relatively high laser induced damage threshold, a relatively broad transmissive band (0.38-5.9 ?m and 6.6-7.08 ?m), a relatively great 2nd-order nonlinear optical coefficient (d15=6.7 pm/V), a relatively great birefringence, a high thermal conductivity (490 Wm?1K?1), and a high chemical stability.

Abstract: A semi-insulating silicon carbide monocrystal and a method of growing the same are disclosed. The semi-insulating silicon carbide monocrystal comprises intrinsic impurities, deep energy level dopants and intrinsic point defects. The intrinsic impurities are introduced unintentionally during manufacture of the silicon carbide monocrystal, and the deep energy level dopants and the intrinsic point defects are doped or introduced intentionally to compensate for the intrinsic impurities. The intrinsic impurities include shallow energy level donor impurities and shallow energy level acceptor impurities. A sum of a concentration of the deep energy level dopants and a concentration of the intrinsic point defects is greater than a difference between a concentration of the shallow energy level donor impurities and a concentration of the shallow energy level acceptor impurities, and the concentration of the intrinsic point defects is less than the concentration of the deep energy level dopants.

Abstract: A technology for growing silicon carbide single crystals by PVT (Physical Vapor Transport) and a technology for in-situ annealing the crystals after growth is finished is provided. The technology can achieve real-time dynamic control of the temperature distribution of growth chamber by regulating the position of the insulation layer on the upper part of the graphite crucible, thus controlling the temperature distribution of growth chamber in real-time during the growth process according to the needs of the technology, which helps to significantly improve the crystal quality and production yield.