Twinning of a Quartz Plate at Low Temperature Using a Laser Beam

We have previously reported an artificial twinning (x-axis inversion) technique that involves the thermal treatment method and the laser beam scanning method for a rotated Y-cut (RY-cut) quartz plate. The heating temperature for twinning was about 520–540°C using the thermal treatment method. Furthermore, in the laser beam scanning method, a high preheating temperature of about 480°C was necessary to obtain a well-controlled twinning pattern. We present here twinning at low temperature (350°C ∼ room temperature) using the laser beam scanning method. This method can be used the potential to form an arbitrary fine twinning pattern at room temperature. High reproducibility of a fine twinning pattern was obtained at a preheating temperature of 350°C. A relatively good twinning pattern was also obtained by the laser beam scanning method without preheating. It was estimated that the shear strain caused by laser irradiation was of the order of 10-4, for the case there the twinning occurred. The large temperature gradient produced in the plate by laser beam irradiation drastically reduced the treatment temperature.