Recently, using self-developed continuous filtration rapid growth equipment, a cuboid Potassium Dideuterium Phosphate (DKDP) boule of 100×100×92 mm³ has been successfully grown without pyramidal {101} face in Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Science.

The dimension of the long seed is 10×10×92mm³ corresponding to [100], [010] and [001] crystallography directions.

By fixing this seed between the upper and lower baffles of the crystal holder and controlling the supersaturation of DKDP solution, the four prismatic faces begin to grow rapidly with the growth rate of 10mm/day. Besides, the upper and lower pyramidal faces are inhibited due to the baffles.

Compared with the point-seed rapid growth method, without pyramidal face growth, the phase distortion and electromagnetic field modulation induced by the boundary between prismatic and pyramidal sectors are eliminated.

Moreover, its yield for the type II triplers is two times higher than that of the point-seed rapid DKDP growth.

Due to the regular shape of crystal without the pyramid sector, the control of supersaturation and flow field will be easy during the growth process, which is beneficial to optimizing crystal quality.

The preliminary test shows that the crystal has no macroscopic defects and the transparency is good.

The successful growth of a medium-size cuboid DKDP boule verifies the possibility of the large aperture DKDP crystal with the self-developed continuous filtration rapid growth equipment and long seed.

Currently, researchers are evaluating the quality of the DKDP crystal comprehensively. In addition, the rapid growth crystal with the aperture >40 cm is in progress.

DKDP crystal (Image by SIOM)