Countries around the world are rapidly developing high-energy laser weapons for military missions on land, sea, air and space. Visions of swarms of small, inexpensive drones filling the skies or riding the waves are encouraging militaries to develop and deploy laser weapons as an alternative to expensive and potentially overloaded missile defense systems.

Laser guns were a staple of science fiction long before lasers were invented. They have also featured prominently in some conspiracy theories recently. Both types of fiction emphasize the need to understand how laser weapons actually work and what they are used for.

How do lasers work?

A laser uses electricity to produce photons, or particles of light. Photons pass through a gain medium, which is a material that creates a series of additional photons and rapidly increases the number of photons. All these photons are then focused into a narrow beam by a beam guide.

In the decades since the first laser appeared in 1960, engineers have developed a variety of lasers that produce photons of different wavelengths across the electromagnetic spectrum, from infrared to ultraviolet. High-energy laser systems with military applications are based on solid-state lasers that use special crystals to convert incoming electrical energy into photons. An important feature of powerful solid-state lasers is that photons are created in the infrared part of the electromagnetic spectrum, so they are invisible to the human eye.

When a laser beam interacts with a surface, it creates different effects depending on the wavelength of the photon, the power of the beam, and the material of the surface. Low-power lasers, which produce photons in the visible part of the spectrum, are useful as light sources for beacons and light shows at mass events. These rays have such a low power that they simply bounce off the surface without damaging it.

Higher power laser systems are used to cut biological tissue during medical procedures. The most powerful lasers can heat, vaporize, melt and etch many different materials and are used for welding and cutting in industrial processes.

In addition to the laser’s power level, its ability to deliver these various effects is determined by the distance between the laser and its target.

laser guns

Building in part on the progress made in high-power industrial lasers, the military is finding more and more applications for high-energy lasers. One of the most important advantages of high-energy laser weapons is that they provide an “infinite magazine”. Unlike traditional weapons such as rifles and cannons, which contain a limited amount of ammunition, a high-energy laser can keep firing as long as it has power.

The U.S. Army uses a high-energy truck-based laser to hit a variety of targets, including drones, helicopters, mortar rounds and missiles. The 50-kilowatt laser is mounted on a Stryker infantry fighting vehicle, and the Army deployed four systems for combat testing in the Middle East in February 2024.

The U.S. Navy has deployed a high-energy laser on ship decks to provide defense against small, fast-moving ocean surface ships, as well as missiles and unmanned aerial vehicles. The Navy installed a 60-kilowatt laser weapon on the destroyer USS Preble in August 2022.

The Air Force is developing high-energy lasers for aircraft for defensive and offensive missions. In 2010, the Air Force tested a megawatt laser mounted on a modified Boeing 747 that hit a ballistic missile during launch. The Air Force is currently working on a smaller weapons system for fighter jets.

Russia appears to be developing a high-energy, ground-based laser to “blind” rivals’ satellites.

Limitations of laser weapons

One of the key challenges facing the military using high-energy lasers is the high power level required to produce beneficial effects from a distance. Unlike an industrial laser, which can only be inches away from its target, military operations require much longer distances. To defend against the next threat, such as a mortar round or a small boat, laser weapons must reach their target before they can do any damage.

But burning materials at safe distances requires tens to hundreds of kilowatts of laser beam power. The smallest prototype laser gun consumes 10 kilowatts of power, approximately equivalent to the power of an electric car. The latest super-powerful laser weapon under development consumes 300 kilowatts of energy, enough to power 30 households. Since high-energy lasers are only 50% efficient at best, they produce a huge amount of waste heat that must be managed.

This means that high-energy lasers require extensive power generation and cooling infrastructure, limiting the types of effects that various military platforms can produce. Army trucks and Air Force fighter jets have the least space for high-energy laser weapons, so these systems are limited to relatively low-power targets like shooting down drones or disabling missiles. Ships and larger aircraft can accommodate larger, high-energy lasers that can punch holes in boats and ground vehicles. Geostationary ground systems have the fewest limitations and therefore the most power, potentially making it possible to blind a distant satellite.

Another major limitation to platform-based high-energy laser weapons relates to the infinite magazine concept. Since a truck, ship or plane must carry the power supply for the laser, which will limit the power of the power supply, the lasers can only be used for a limited time before recharging their batteries.

The US military is conducting field tests of various high-energy laser weapon systems.

High-energy laser weapons also have fundamental limitations, including reduced effectiveness in rain, fog, and smoke that disperse laser beams. Laser beams also need to stay locked on their target for several seconds to deal damage. The current prototype laser weapon also poses a challenge in terms of sustainability in war zones.

There is no fire from the sky

In recent years, a new conspiracy theory has emerged that attackers used airborne high-energy lasers to start wildfires in California, Hawaii and Texas. This is unlikely for several reasons.

First, the level of power required to ignite vegetation from the sky with a high-energy laser would require a large power supply mounted on a large aircraft. An aircraft of this size was clearly visible just before the fire broke out. Second, in some images purporting to show fire, the laser beams are green. High energy laser beams are invisible.

what happens next

In the future, high-energy laser weapons are likely to continue to improve with increasing power levels, expanding the target range over which they can be used. New threats posed by cheaply armed drones, such as those used in conflicts in the Middle East and Ukraine, raise the possibility that high-energy lasers will find non-military uses, such as protecting civilians from terrorist attacks. Source