Gadolinium Yttrium Garnet (Gd:YAG) is a variation of Nd:YAG with microwave and laser applications. NdYAG ( neodymium-doped yttrium aluminium garnet; NdY3Al5O12) is a Crystal that is used as a lasing medium Microwaves are electromagnetic waves with Wavelengths ranging from 1 mm to 1 m or frequencies between 0 A laser is a device that emits Light ( Electromagnetic radiation) through a process called Stimulated emission.