Optical element with sapphire crystallographic structure having plurality of crystal planes

A method for providing an optical element, the method comprising:

• obtaining a sapphire crystal of sufficient size for the optical element, the optical element having a length in a direction of a first axis and a width in a direction of a second axis, wherein the length is greater than or equal to the width;
• determining a sapphire crystallographic structure having a plurality of crystal planes;
• defining a first crystal plane axis to be perpendicular to the first and the second axis, a second crystal plane axis to be parallel to the first axis and a third crystal plane axis to be parallel to the second axis;
• and
• machining the sapphire crystal using the defined crystal plane axes to provide the optical element.