Yttrium Aluminum Garnet, A widely used solid-state crystal which is composed of yttrium and aluminum oxides which is doped with a small amount if the rare-earth neodymium.

YAG Laser

A solid-state laser that uses a neodymium-doped yttrium aluminum garnet (YAG) crystal as the lasing medium. The principal output of this laser is at 1064nm. 
Nd:YAG lasers are available in cw and pulsed configurations and are used extensively in industrial applications for welding, cutting, and laser marking.

Young's Modulus

The elastics modulus for tension, or tensile stress in a material, and is defined as the force per unit cross section of the material divided by the fractional increase in length resulting from the stretching of a standard rod or wire of the material.