Download (4Mb) - Etheses - Saurashtra University

Chapter II Solution Growth….
diameter and high perfection. Because of the highly stressed areas
disappeared in the non-growing prism faces, this technique was unique for
KDP. It can also be applied, the authors pointed out, to similar crystals with a
needle-like habit where pyramidal faces do grow but prism faces do not.
For high power laser application quite large size KDP and DKDP
crystals are needed and attempts have been made to grow them in large
dimensions by various authors. In 1983 an attempt was made to grow 40 x 40
cm 2 cross-section and 100 cm length KDP crystals by Newkirk et al [64]. KDP
and DKDP crystals have been grown with the sizes up to 57 x 57 cm 2 in cross
section and about 55 cm in height by Zaitseva et al [65]. It is also important to
control habit during the growth of KDP crystals to achieve the large size
crystal with specific habit for desired applications. Zaitseva et al [66] proposed
certain measures for the habit control. The ratio of dimensions along the
crystallographic axis was controlled by (i) creation of special dislocation
structure during the seed regeneration process and (ii) change in the
orientation of the seed. The authors applied these techniques to grow KDP
and DKDP crystals of various habits at 100-20 mm/day to the linear sizes of
90 cm.
The effect of bacteria in KDP solution on the growth habits of KDP
crystals has been explored by Sasaki et al [67]. They found hillocks only on
the tapered prismatic surfaces of KDP crystals grown by solution containing
live bacteria. The possible interpretation was proposed as biochemical
reaction between bacteria and KDP crystals.
87