Embodiments of the present disclosure may provide a system for preparing a crystal. The system may include a furnace, a heat insulation drum, a crucible component, a resistance heating component, and a heat insulation layer. The heat insulation drum may be located inside the furnace. The crucible component may be located inside the heat insulation drum. The resistance heating component may include a heating body. The heating body may include a plurality of heating units. The plurality of heating units may form a uniform temperature field. The heat insulation layer may be located around an outer side of the plurality of heating units, a top portion of the heat insulation drum, and/or a bottom portion of the crucible component.

One or more embodiments relate to a method for controlling fiber growth and fiber diameter in a laser heated pedestal growth (LHPG) system so as to provide long, continuous single-crystal optical fibers of uniform diameter. The method generally provides three independent parameter feedback controls to control the molten zone height, laser power, and fiber drawing rates simultaneously in order to reduce the mismatch between instantaneous diameter changes and current diameter. The method permits the growth of fibers with non-uniform diameters along the fiber's length. The method also provides the capability to stop the LHPG system, remove the exhausted pedestal feedstock with a second pedestal feedstock, and restart the LHPG system to provide a continuous fiber.

A phosphor having a variable wavelength and a light irradiation device having said phosphor. This phosphor contains an activating agent, and has a concentration gradient of the activating agent along at least one direction.

In a bismuth-substituted rare earth iron garnet single crystal film production method, the bismuth-substituted rare earth iron garnet single crystal film expressed by the composition formula (Ln.sub.3-aBi.sub.a)(Fe.sub.5-bA.sub.b)O.sub.12 is grown using a substrate of paramagnetic garnet with a lattice constant of Ls. The method includes forming a buffer layer with an average lattice constant of Lb (where Lb > Ls) on the surface of the substrate with a thickness of 5 to 30 .Math.m, and growing a target bismuth-substituted rare earth iron garnet crystal film with an average lattice constant of Lf (where Lf > Lb) with a thickness of 100 .Math.m or more overlaid on the buffer layer. The rate of lattice constant change in the buffer layer is steeper than the rate of lattice constant change in the bismuth-substituted rare earth iron garnet crystal film.

In a bismuth-substituted rare earth iron garnet single crystal film production method, the bismuth-substituted rare earth iron garnet single crystal film expressed by the composition formula (Ln.sub.3-aBi.sub.a)(Fe.sub.5-bA.sub.b)O.sub.12 is grown using a substrate of paramagnetic garnet with a lattice constant of Ls. The method includes forming a buffer layer with an average lattice constant of Lb (where Lb > Ls) on the surface of the substrate with a thickness of 5 to 30 .Math.m, and growing a target bismuth-substituted rare earth iron garnet crystal film with an average lattice constant of Lf (where Lf > Lb) with a thickness of 100 .Math.m or more overlaid on the buffer layer. The rate of lattice constant change in the buffer layer is steeper than the rate of lattice constant change in the bismuth-substituted rare earth iron garnet crystal film.

The present disclosure provides a method for preparing a doped YAG single crystal fiber. The method may include preparing a doped YAG crystal rod; preparing a doped YAG single crystal fiber core by immersing at least a portion of the doped YAG crystal rod in an acid solution; performing a cylindrical surface polishing operation on the doped YAG single crystal fiber core by causing a stirrer to rotate to drive a polishing liquid to rotate; placing the doped YAG single crystal fiber core into a growth zone of a growth chamber and placing a raw material into a dissolution zone of the growth chamber; heating the growth zone and the dissolution zone by a two-stage heating device, respectively; and preparing a doped YAG single crystal fiber by growing a YAG single crystal fiber cladding on a surface of the doped YAG single crystal fiber core.

The present disclosure provides a method for preparing a doped YAG single crystal fiber. The method may include preparing a doped YAG crystal rod; preparing a doped YAG single crystal fiber core by immersing at least a portion of the doped YAG crystal rod in an acid solution; performing a cylindrical surface polishing operation on the doped YAG single crystal fiber core by causing a stirrer to rotate to drive a polishing liquid to rotate; placing the doped YAG single crystal fiber core into a growth zone of a growth chamber and placing a raw material into a dissolution zone of the growth chamber; heating the growth zone and the dissolution zone by a two-stage heating device, respectively; and preparing a doped YAG single crystal fiber by growing a YAG single crystal fiber cladding on a surface of the doped YAG single crystal fiber core.

Provided is a method for producing a crystal body that can obtain a crystal body having a relatively large size and a more uniform composition, and a novel single crystalline phosphor obtained by the above producing method. The single crystalline phosphor contains YAG or LuAG as a main component and at least one element of Ce, Pr, Sm, Eu, Tb, Dy, Tm, and Yb as an accessory component. In a cross section of the single crystalline phosphor, a uniform concentration region in which the accessory component is uniformly distributed is located in a central portion of the cross section, and an area ratio of the uniform concentration region to a cross-sectional area of the cross section is 35% or more.

Provided is a crucible capable of improving uniformity of a temperature distribution of a melt drawn by a seed crystal and obtaining a crystal having a more uniform composition, and a crystal growth equipment including the crucible. The crucible includes a melt storage portion 24 that stores a melt that is a raw material of a crystal, and a die unit 34 that controls a shape of the crystal. The die portion 34 includes a die flow path 36 through which the melt 30 is passed from a storage portion outlet 32 provided on a bottom surface of the melt storage portion 24 toward a die outlet 38 provided on an end surface of the die portion 34. The die flow path 36 includes a narrow portion 36a1 whose flow path cross-sectional area is smaller than an opening area of the die outlet 38.

The present disclosure provides a method for crystal growth. The method may include at one of the following operations: weighing reactants for growing an oxide crystal after a first preprocessing operation is performed on the reactants; placing the reactants, on which a second preprocessing operation has been performed, into a crystal growth device after an assembly preprocessing operation is performed on at least one component of the crystal growth device, wherein the at least one component of the crystal growth device includes a crucible, the assembly preprocessing operation includes at least one of a coating operation, an acid soaking and cleaning operation, or an impurity cleaning operation; introducing a protective gas into the crystal growth device after sealing the crystal growth device; activating the crystal growth apparatus to execute the crystal growth; and adding reactant supplements into the crystal growth device in real-time during the crystal growth.