In order to obtain maximum conversion efficiency, angle tilting is normally used to reach phase-matching direction. There are two axes for tilting crystal angles as shown in the right figure. Because the NLO crystals provided by Dream Lasers are normally cut in a principal crystal plane, conversion efficiency isn't sensitive to the angle tilting around n-axis. However, it is very sensitive to the angle tilting around m-axis which is called tilting axis of NLO crystals and is normal to marked surface. Customers have to pay great attention when rotating the crystal around m-axis. A crystal mount with angle accuracy of about 5 arc second is recommended.