What is an Excimer Laser primarily characterized by?

An Excimer Laser is primarily characterized by its use of a reactive gas in an excited state. This type of laser generates energy through the combination of a noble gas (such as argon or krypton) with a reactive halogen gas (such as fluorine or chlorine). The term "excimer" refers to the temporary diatomic molecule formed from these gases when they are excited to a higher energy state. When the excited state returns to a lower energy state, it emits a laser pulse, typically in the ultraviolet (UV) spectrum.

This characteristic makes Excimer Lasers particularly useful in applications like photolithography and laser eye surgery, where UV light can be precisely controlled to ablate material or reshape the cornea. The unique properties of the reactive gas and the specific molecular combinations involved in the process distinguish Excimer Lasers from those that rely on solid, liquid, or other gas media.