A beam homogenizer is a device that smooths out the irregularities in a laser

Laser

A laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...

 beam profile and creates a more uniform one. Most beam homogenizers use a multifaceted mirror

Mirror

A mirror is an object that reflects light or sound in a way that preserves much of its original quality prior to its contact with the mirror. Some mirrors also filter out some wavelengths, while preserving other wavelengths in the reflection...

 with square facets. The mirror reflects

Reflection (physics)

Reflection is the change in direction of a wavefront at an interface between two differentmedia so that the wavefront returns into the medium from which it originated. Common examples include the reflection of light, sound and water waves...

 light at different angles to create a beam with uniform power across the whole beam profile (a "top hat" profile). Some applications of beam homogenizers include their use with excimer laser

Excimer laser

An excimer laser is a form of ultraviolet laser which is commonly used in the production of microelectronic devices , eye surgery, and micromachining....

s for making computer processing chips and with CO₂ lasers for heat treating.