PH4858 Directed Energy Weapons

This course teaches the physics and engineering concepts underlying directed energy (DE) weapons. Topics include an introduction to laser physics, history of DE, advantages/disadvantages of DE, types of DE technologies, output power requirements for different missions, current Navy and DoD programs, target damage mechanisms, beam propagation through the atmosphere, thermal blooming, power and cooling considerations, and beam control. Where appropriate, both high energy lasers and high power microwave technologies will be discussed. The course will include modeling of the propagation of a high energy laser beam through the atmosphere and of damage effects.

Prerequisite

PC2911 or familiarity with MATLAB. PH3352 or permission of the instructor.

Lecture Hours

4

Lab Hours

1

Course Learning Outcomes

Upon successful completion of this course, students will:

• Understand the basic concepts of directed energy weapons (in particular, high energy lasers), including major components, typical parameters, advantages and disadvantages, and potential military applications.
• Understand the basic physics of lasers, including atomic transitions, pumping, population inversion, stimulated emission, light amplification, and coherence.
• Perform simple calculations of transition rates and gain in a laser.
• Understand the factors that affect output power and efficiency of a laser weapon, and the input power and cooling requirements.
• Know the primary types of lasers, their advantages, and disadvantages.
• Understand the basic principles of fiber lasers, including total internal reflection, numerical aperture, optical modes, methods of pumping, effects that limit their output power, and beam combination techniques.
• Understand the effects of the atmosphere on the propagation of laser beams, including absorption, scattering, turbulence, and thermal blooming.
• Given laser and atmosphere parameters, estimate spot size and irradiance on a target at a given range and altitude using simple “scaling law” formulas and a beam propagation code developed in the course.
• Understand the basic principles of beam control, including beam director design, adaptive optics, targeting and tracking.
• Understand the basic principles of target lethality, including damage mechanisms, soft vs. hard kills, and the key factors that affect probability and time to kill.
• Given laser irradiance, spot size, and target material properties, estimate the required dwell time to melt through a given thickness of a target using simple thermodynamic formulas.