The Use of Diffractive Optics in Directed Energy Systems

Directed energy laser weapon systems use concentrated laser power to damage or even completely destroy a specific target. The United States and several other countries explore the deployment of laser weapon systems actively and strive to integrate them on the battlefield. The potential cost of directed energy laser weapon systems per shot is low compared to traditional weapons. In theory, a directed energy system can be considered as a high laser power system with the capacity of unlimited firing. However, there are certain uncertainties about the stability and lifetime of this system over the long term. Along with this, adverse weather conditions like mist and haze can affect the effectiveness of some directed energy laser weapon systems.

The Challenges of Laser Weapon Systems

Even though many years of research have helped accomplish significant technological advancements there are still multiple obstacles to laser weapon system’s widespread adoption. The major challenges of directed energy systems are maintaining the stability of the laser systems over a long period, meeting lethality requirements by maintaining precision and narrow bandwidth and ensuring high laser damage thresholds of optics (LDT).

Therefore, laser weapon systems require a combination of several laser sources coherently to maximize efficiency and minimize beam divergence to accomplish high power density on the target. Earlier, attaining high laser power was very difficult due to these challenges. However, now, the use of Diffractive Optical Elements or DOEs in laser weapon systems has helped overcome many of the above-mentioned issues.

The Use of Diffractive Optics in Directed Energy Systems

Diffractive Optical Elements or DOEs are Useful for beam deflection and  beam shaping. These optical elements transform an input beam into a well-defined output beam with a uniform intensity profile and sharp edges, or deflector a beam so that it is parallel to the optical axis. DOEs meet several requirements of laser weapon systems, such as

• These optical elements can withstand high laser power.
• They offer absolute angular accuracy and no tolerances for splitting angles or deflection.
• Being monolithic, Fused silica windows,  they can tolerate harsh environmental conditions.
• As DOEs are lightweight, compact, and thin, it is easy to integrate these optical elements into powerful laser systems. This is why DOEs have significant laser applications in aerospace and defense.

Conclusion

Diffractive optical elements have significant applications in effectively combining coherent laser beams in directed energy laser weapon systems. There are different types of DOEs, including beam splitters, beam shapers, and other types of DOEs. These optical elements are thin, and flat and show high accuracy and laser damage thresholds (LDT). By combining multiple input beams coherently, they generate high laser power and distribute the power according to the pre-defined specifications. Above all, diffractive optical elements are useful for directed energy laser weapon systems.