Directed Energy Futures 2060: Visions for the Next 40 Years of U.S. Department of Defense Directed Energy Technologies [open pdf - 6MB]
From the Introduction: "Directed Energy (DE) is defined for military applications as the ability to project electromagnetic energy either broadly to provide information probing of the battlespace, or in a focused manner sufficient to produce a defensive or offensive effect at militarily relevant distances within the battlespace. The military significance of Directed Energy Weapons (DEWs) has long been recognized for ability to engage at the speed of light, propagating vast distances with precision. Other benefits include potentially deep magazines, meaning the capability to fire many shots without need to physically rearm the weapon, and low cost per shot. DE can also actively probe targets and threats, i.e. laser pointers (commonly called designators), laser and radiofrequency (RF) tracking, also called radar. The final benefit worth mentioning, is the ability to cause scalable and flexible effects, to include destructive, damaging, disruptive, non-lethal, deceptive, and unattributable effects. Today in the early 2020s, world-wide DE already plays important military roles in counter-air defense, target identification, tracking, counter intelligence search & reconnaissance (ISR), and electronic warfare (EW)."
Air Force Research Laboratory: https://www.afrl.af.mil/