A laser shock peening device and components thereof. The optical system of the laser peening device includes sapphire optical elements (318), such as a lens (318b) or a prism (318a). A water channel (322) is provided in a pen (206) for the laser shock peening device that has a curved flow path to direct the water. An air conduit (400) in the pen (206) provides a stream of air to the surface receiving the laser shock peening treatment.