With the technological advancement on optoelectronics, effective use of laser technology has become an evident part of modern warfare. A directed energy laser weapon is capable of damaging target equipment using concentrated beam of electromagnetic energy. My series articles about effective use and fundamentals of Directed Energy Weapons (DEWs) covered discussion about Particle Beam Weapons and Microwave Based Weapons in the previous chapters. Let us discuss about Laser Based Weapons today. Energy weapon concept, credit: Pixabay, license: CC0 1.0 These laser weapons can be both used for lethal and non-lethal operations. The lethality of the laser weapon is much dependent on wavelength and power density of the respective laser. A wavelength based laser classification bar is shown in Figure 1. Figure 1: Laser wavelengths. credit: Wikimedia Commons author: Danh license: CC BY-SA 3.0

Categories of Laser

Lasers can be classified into several forms in terms of wavelength, operation and lethality. Lasers used in directed energy weapon preferably have shorter wavelength and highest beam quality. The most commonly used laser types are discussed here:

Gas Laser

E. Gerry and A. Kantrowitz invented the gas lasers back in 1966. This type of lasers use a gas mixture to generate laser beam. A gas laser is typically having a combustion chamber and supersonic nozzle expansion mechanism. The combustion produces relatively high pressured gas mixture which initiate the population inversion of laser. CO₂ gas lasers have industrial implementation including welding & cutting operations. Glass medium can absorb the wavelength produced by a CO₂ gas laser. This phenomenon is used in laser weapons for non-lethal operations like damaging windshields of enemy vehicles.

Chemical Laser

A chemical reaction works as the source of energy in a chemical laser system. This type of lasers are capable of generating very high output power continually. A stream of gas is produced by the chemical reaction. The molecules of gas stream are excited up to a certain level. Laser particles are then produced by this excited molecules with the help of injected gas. Chemical lasers are used in cutting operations in industries and can also be used to make lethal laser based energy weapons.

Solid-State Laser

Solid-state laser gain medium is used to produce the electromagnetic energy in Solid-State Lasers (SSLs). This lasers are electronically operated which makes them lighter in weight and suitable for compact, robust usage. Having shorter wavelength, SSL generates comparatively lower output power. Researchers are working to reduce the amount of waste heat. This will significantly improve the output power in solid-state laser devices. SSLs also have the advantage of deep magazine and lower operating cost. A solid-state laser having 100 kW output power can operate effectively against incoming mortar shell and unmanned air vehicle attack.

Fiber Laser

The fiber laser technology is an advanced branch of solid-state lasers. The gain medium of this laser is composed of optical fibers doped with proper materials. The optical fiber contains laser diodes which are coupled with fibers. It has small aperture that helps to generate very high intensity output laser beams. The magnitude of the fiber laser can possibly reach twice higher than the ordinary SSLs. Fiber lasers are comparatively stronger and more reliable than other laser systems. The shorter wavelength of this type of lasers offers capability of operating in longer range. The only issue with the present fiber technology is the complexity of the entire system which is presumably be solved within a few years of technological advancement.

Components of Laser Based Weapons

The laser based directed weapon has two main parts. An overview about the two main components are given below:

Laser Source

The laser source works as the generating station for the energy weapon. This is an integral part of high powered laser weapons. It produce the required electromagnetic beam for a certain period of time to generate the laser. This system provides maximum power density within the laser at a target location. Several technologies have been used to power up the laser based weapons. CO₂ and chemical based laser sources were used during early period of this weapon development. Recent advancement in solid state technology has made it one of the most viable source for laser based directed weapon system. In terms of lethal operations, Chemical Oxy Iodide Laser (COIL) system is mostly used because of its capabilities of generating power in very high scale with shorter operational wavelength.

Figure 4: Components of Laser Weapons. credit: author

Beam Control Mechanism

Beam control equipment are used to accurately point the target and to guide the electromagnetic energy in a specific manner. Beam control mechanism performs following operations:

Target tracking

Beam directing

Beam transportation

Target tracking operation is performed using camera equipment mounted with telescope mechanism. Target tracking system has crucial role against fast moving targets like missiles, aircrafts and Unmanned Aerial Vehicles (UAVs). The beam is directed towards the specific target using telescope mechanism. The weapon’s lethal range is much dependent on the aperture size of the telescope. A cascaded arrangement of mirrors is used to direct the laser beam towards the telescope. This transportation system connects the laser source with the telescope.

Laser Weapon Operations

With the advancement of military technology, implementation of laser based directed energy weapons are becoming crucial part of modern warfare. Improved lethality and flexible operation capabilities enable the use of laser weapons in both defensive and striking operations.

Defensive Operation

Laser weapons can effectively be used in defensive operations. It has the potential to provide self-defense features for land, air and naval military units. Laser weapons are capable of damaging the incoming fire threats like rockets, mortar shells etc. Laser based weapons offers increased survival rate for supersonic aerial platforms. The defensive use of laser weapons can be described as follows:

Improved self-defense capability for multi-disciplinary military operations.

Airborne laser system strengthen the defensive parameters of aircrafts and subsonic equipment.

Ground based laser system offers troops protection and better land mobility.

Laser weapons can be mounted on tanks to counter incoming missile or UAV attacks.

Laser system provides effective defense from cruise missiles on naval defense. Allowing the fleet to operate from a close ranger of enemy surveillance area.

Laser weapon also provides better successful operation rate against sea skimming anti-ship missiles.

Laser based directed energy weapons can offer protection of valuable assets like government structure or supply storage.

Offensive Operation

Laser weapons offers both lethal and non-lethal striking operations. The use of laser weapons in offensive operations are mostly based on the accuracy and speed of laser propagation. This type of weapons can be used against enemy defensive system to disable the tracking and sensing operation of enemy defensive utilities. The offensive implementation of laser weapons can be described as follows:

Airborne striking laser weapons can be used against ground targets.

Laser weapons has effective use in countering sniper operation with the help of acoustic and optical sensors.

Non-lethal laser weapons can disrupt enemy’s satellite or radio signal.

Another use of non-lethal laser weapons are in destroying enemy utility equipment like power transformers, radar devices etc.

Laser weapons can be implemented on submarine periscope to engage ships or lower altitude aircraft.

An example of laser weapon demonstration can be observed from the video shown below. The video is licensed under CC BY-SA 3.0.

Laser weapon demonstration by US Navy available on Wikimedia Commons

Laser weapons have several advantages over the conventional military weapons. The most effective advantages of laser based weapons are discussed below:

Laser weapons have speed-of-light delivery which offers fast engagement operation even for longer distance targets.

It offers the capability of engaging multiple target and also have very fast retargeting ability.

Only a few laser types (i.e chemical laser) needs external ammunition supply. Most of the laser weapons only need electrical power for operation.

Laser weapons have deep magazine and comparatively lower cost per shot.

Laser weapons offer better accuracy and precision based targeting.

Laser based weapon systems have some operational limitations also. The limitations of laser based weapons are given below:

Laser weapons are highly dependent on line-of-sight implementation.

The atmosphere has significant effect on laser propagation.

Laser weapons have range limits due to diffraction effect of the optical aperture.

The lethality of the weapon is highly dependent on the target material.

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Conclusion

Laser based directed energy weapons are constantly being used in current military operations across the globe. The mobility and precision based accuracy of laser weapons make it a viable option in both defense and attacking operation. Recent advancement on laser technology increased the potential to implement laser weapons in land, air and marine platforms. Ongoing researches are expected to improve the credibility of laser based weapons in upcoming years.

References

Military technology: Laser weapons get real, Andy Extance, Nature

The Promise and Problem of Laser Weapons, Catherine MacRae, Air Force Magazine

Lasers As Weapons, Kathy Sheehan, Web document

How Space Wars Will Work, Kevin Bonsor, Web document

High Energy Laser Weapon Systems, MBDA, Web document

Fiber Lasers Mean Ray Guns Are Coming, Jeff Hecht, IEEE Spectrum

Analysis of High Energy Laser Weapon Employment from a Navy Ship, ANG, Ching Na, Calhoun Archive

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My sincere gratitude to @scienceangel for her help in mentoring this article.

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