X. R. Huang

The growth defects in self-frequency-doubling laser crystal NdxY1 − xAl3(BO3)4

The growth defects in flux-grown NdxY1 − xAl3(BO3)4 (NYAB) single crystals have been investigated by means of chemical etching and synchrotron radiation techniques. The band-shaped and polysynthetic twins were detected by optical microscopy due to the difference in etching rates between the host crystal and the twin. In the meantime, the orientation and symmetry of the twins were analyzed from their etching patterns. A large number of etch pits with regular shapes were also found on the surface, and these etch pits correspond to outcrops of the dislocations originating from the seed crystal or inclusions.

The formation mechanisms of dislocations and negative crystals in LiB3O5 single crystals

Dislocations and negative crystals in LiB3O5(LBO) single crystals were investigated by white-beam synchrotron radiation topography (WBSRT) and birefringence image. The WBSRT revealed that the grown-in dislocations are mainly pure screw or edge types with the Burgers vectors in the low index directions on the (010) lattice plane. Based on the structure analysis, the cause of the formation of dislocations can be interpreted in terms of the loose packing of B-O rings on the (010) lattice plane. In addition, the negative crystals, which were observed by the birefringence image, tend to present at regular shapes which are similar to that of the host crystal, It is proposed that the negative crystals result from the formation of liquid parent inclusions and the following inward growth.

Growth defects in Nb:KTP crystals observed by synchrotron radiation topography

Abstract The growth striations, growth sector boundaries and grown-in dislocations in flux-grown Nb-doped KTiOPO 4 crystals have been investigated by white-beam synchrotron radiation topography. The distribution of growth sectors, which mainly consists of {011} and {201} sectors, is clearly shown and characterized, and the effects of growth striations on the non-critical phase matching along the [100] direction are discussed.

Synchrotron radiation topography studies of twinning in NdP5O14 crystals

An investigation of twin structures in NdP5O14 single crystals has been undertaken using white‐beam synchrotron x‐ray topography. The so‐called a‐type twins along the a axis are clearly revealed in the topographs. The displacements of the images that arise from the twins are directly measured in different topographs. With the measured values, the monoclinic distortion angle δ(δ=β−90°) is calculated, which is in good agreement with the unit cell parameters. A fine‐beam Laue diffraction pattern of the twin has also been taken which is well consistent with its simulation. From these results, the twin structures of NdP5O14 are discussed.

Investigation of Optical Inhomogeneities and Growth Defects in Flux‐Grown Nb:KTP Crystals

Optical inhomogeneities and growth defects in flux-grown Nb-doped potassium titanyl phosphate crystals have been investigated. The growth striations, growth sector boundaries and dislocations are revealed by white-beam synchrotron radiation topography. All of the observed dislocations are growth induced and no ferroelectric domains are found in the crystals. It is believed that the main reason for causing the instability of the 90° non-critical phase matching along the 2-direction is related to the growth striations, especially of {011} sectors.

X-ray topographic study of twins in Nd x Y(1−x)Al3(BO3)4 crystal

SummaryThe twins in self-frequency-doubling laser crystal NdxY(1−x)Al3(BO3)4 (NYAB) have been investigated by the transmission synchrotron topography and conventional Lang topography. It has been found that the twins in NYAB are similar to Brazil twins in natural quartz,i.e. the twin element is the mirror plane of type

Orbitronic effect on the magnetic reconstruction of monocell SrMnO3 on ferroelectric BaTiO3 substrate

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X-ray topographic investigation of tungstate flux-grown KTiOAsO4 crystals

normal to the twofold (electric) axis. The twin is also discovered to have the shape of lamella and the twin boundaries are