Laser weapons are high powered lasers that emit coherent beams of light to damage their target. However, they require enormous amounts of energy, so a personal-based application is a little tricky. They are favored by the Amarr Empire and, apparently, the Jove as well.
Some laser weapons have an integral power supply but are not very powerful and thus largely insufficient for engaging targets in heavy body armor. Other types, especially military rifles, use an external miniature reactor strapped to the users back and can provide excellent firepower with extraordinary accuracy.
On a side note, lasers do not require ammunition, only energy, and thus ease the logistic burden of ground forces. Handheld laser weapons are predominantly used by the Amarr and in the Khanid Kingdom.