Laser weapons work by stimulating electrons with enough energy that they emit light waves that can be amplified and concetrated. Most laser weapons, weren't really weapons and more like tracking devices. That is until the LaWS or Laser Weapon System was made. Website Link
The LaWS was able to harnass 30 thousand watts of energy and focus it on one spot. It made and put into use between the years 2010-2014. It was mainly designed to destroy small devices such as drones or UAV's.
Nowadays, the Navy is planning to attach an even more powerful laser weapon called the HELIOS or High Energy Laser with Integrated Optical-dazzler and Surveillance system. The LaWS was able to output 30 kilowatts of energy. The Helios doubles that at 60 kilowatts. Able to incinerate drones and even larger objects flying or sailing.