High Energy Lasers
Green, David
2/16/2016
David Green
85 NW Sleret Ave
Gresham, Oregon
david.green35@verizon.net
503-492-2108
High Energy Lasers used as Weapons
David Green
Advancements in technology has brought about many changes in our everyday lives.
Some of these changes are beneficial and some are not. In our race for advancement, we have
developed many weapons, none of them as formidable as the laser. Lasers have great potential in
industry, surgery and communications. To understanding how society has advanced towards
high-energy lasers: a better understanding of their development and functionality is needed.
Lasers come in different forms and construction. However, all lasers contain an energized
substance that has the properties to intensity the light passing through it. This substance can be
made from a variety of mediums. The mediums can be in any of the principle states such as
solid, liquid or gas. These mediums must have the ability to store energy until it is released as
light.
The variation of substance establishes the medium’s factor. This factor contributes to the lasers
amplification, along with the wavelength and intensity of the incoming light, and the length of
the medium.
Figure 1 diagram of a laser in operation
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To increase the intensity of the light beam that is passing through the medium, energy
must be added. The energy is supplied by an additional source. The process is known as
“pumping.” The photon’s energy (E) is determined by its frequency (V) and Planck’s constant
(h). Photon emission occurs when the electron drops from one state to a lower state.
The energy source causes the electrons in the medium to become excited. While
absorbing the energy the electrons will climb into a higher state. This state is unstable and the
electrons will fall back to the lower state, however they will emit photons. The photons will
travel in a multitude of directions. On each end of the medium are attached mirrors, one of which
has a lesser reflective property than the other. Some of the photons strike the mirrors and are
reflected back along the length of the medium.
Figure 2 Photon building up energy
Lasers operate at relative wavelengths; in appendix A is a chart of laser types and their
corresponding wavelengths.
What makes a high energy laser (HEL)? When laser energy is more that 1 Joule/pulse,
and the average power exceeds 100 Watts, then the laser is considered high energy. Actual
systems develop up to 100,000 Joules, and an average power of 1,000,000 Watts. The peak
power on the pulsed lasers may even exceed 10,000,000,000 Watts.
At the High Energy Laser Systems Test Facility (HELSTF) located in White Sands
Missile Range, New Mexico, resides the Mid Infrared Advanced Chemical Laser (MIRACL), the
United States' most powerful laser. The Mid-Infrared Advanced Chemical Laser (MIRACL) was
the first megawatt-class, continuous wave, chemical laser built in the free world. It is a deuterium
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fluoride (DF) chemical laser with energy spectra distributed among about 10 lasing lines
between 3.6 and 4.2 microns wavelength. It remains the highest average power laser in the US.
MIRACL operation is similar to a rocket engine in which a fuel (ethylene, C2H4) is burned with
an oxidizer (nitrogen trifluoride, NF3).
Free, excited fluorine atoms are one of the combustion products of MIRACL’s exhaust.
Just downstream from the combustor, deuterium and helium are injected into the exhaust.
Deuterium combines with the excited fluorine to give excited deuterium fluoride (DF)
molecules, while the helium stabilizes the reaction and controls the temperature. The laser's
resonator mirrors are wrapped around the excited exhaust gas and optical energy is extracted.
The cavity is actively cooled and can be run until the fuel supply is exhausted.
The laser's output power can be varied over a wide range by altering the fuel flow rates
and mixture. This laser produces a beam in the resonator is approximately 21 cm high and 3 cm
wide. Beam shaping optics are used to produce a 14 cm square beam shape, which is propagated
through the rest of the beam train.
MIRACL ready for action
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High Energy Lasers
Green, David
2/16/2016
A Beam Director is mounted on top and consists of a large aperture (1.8 meter) gimbaled
telescope with optics to point the MIRACL at the target. The high power clear aperture is 1.5
meters. The remaining 0.3 meters is normally reserved for a tracker using the outer annulus of
the primary mirror. The system is extremely agile and capable of high rotation and acceleration
rates. The targeting device (SLBD) weighs 28,000 pounds, of which 18,000 are on the movable
portion. The SLBD can also be used as a sensor platform.
The telescope is capable of focusing from a minimum range of 400 meters to infinity. A
suite of infrared and visible sensors on the top of the gimbal (off axis from the HEL aperture) is
used to acquire and track the target. These sensors look through a 40 cm telescope that can focus
over the same range as the SLBD telescope and also correct for parallax between the two lines of
sight. Boresight between the SLBD telescope and the sensor is maintained by an automatic laser
alignment system. In addition, an aperture-sharing element in the high power beam path makes it
possible to track a target through the full 1.5 meter telescope aperture even when the high power
beam is propagating.
Artist rendering of the SLBD
These elements have been combined into an integrated system that can acquire and track
targets at extended ranges, accept a very high energy beam, focus and aim the beam on a moving
target, and keep this beam at the same position as long as necessary to destroy or disable the
target. The SLBD has successfully engaged five BQM-34 drones as well as a supersonic Vandal
missile, all at tactically significant ranges.
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High Energy Lasers
Green, David
2/16/2016
This development has brought the army and air force new weapons. The Airborne Laser
(ABL) weapon system consists of a high-energy, chemical oxygen iodine laser (COIL) mounted
on a modified 747-400F (freighter) aircraft to shoot down theater ballistic missiles in their boost
phase. A crew of four, including pilot and co-pilot, would be required to operate the airborne
laser, which would patrol in pairs at high altitude, about 40,000 feet, flying in orbits over friendly
territory, scanning the horizon for the plumes of rising missiles. Capable of autonomous
operation, the ABL would acquire and track missiles in the boost phase of flight, illuminating the
missile with a tracking laser beam while computers measure the distance and calculate its course
and direction. After acquiring and locking onto the target, a second laser, with weapons-class
strength, would fire a three to five second burst from a turret located in the 747's nose, destroying
the missiles over the launch area.
Artist rendering of THEL in action
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High Energy Lasers
Green, David
2/16/2016
The U.S. Army Space and Strategic Defense Command is working on a new active
defense weapon system concept to enhance protection for combat forces and theater level assets
for the Force XXI Army. The mobile Tactical High Energy Laser, or THEL, weapon system
would provide an innovative solution for the acquisition and close-in engagement problems
associated with so-called "dumb munitions" -- a primary concern because counter-battery fire
may not be an option in densely populated areas.
In its first live warhead test, the Tactical High Energy Laser (THEL) system intercepted
and destroyed an armed Russian-made Katyusha rocket within seconds of its launch at the White
Sands Missile Range. The system detected the 10-foot-long, 5-inch-diameter rocket with its radar
before shooting it down at the speed of light with any difficulty.
The army’s LBL program utilizing the THEL data.
Given the advancements in technology and development in high-energy lasers,
military defense weapons of war would naturally follow. The research into HEL is mainly
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2/16/2016
funded by the federal government. This double edge sword has given industry opportunities that
would never have been available. Research continues, weapon development along side gives
America the advancement in industry to compete in today’s global economy
Star wars program SBHEL in construction
MIRCLE night test at White Sands
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Appendix A Wave Lengths Of The More Common Laser Types
Wave
Laser Type
Media
Length (s)
Excimer Gas Lasers
Argon Fluoride
Nanometers
(UV)
193 nm
(UV)
222 nm
Krypton Fluoride
(UV)
248 nm
Xenon Chloride
(UV)
308 nm
Xenon Fluoride
(UV)
351 nm
Nitrogen
(UV)
337 nm
Helium Cadmium
(UV)
325 nm
Krypton
Chloride
Gas Lasers
(Violet
Helium Cadmium
441 nm
)
Argon
(Blue)
488 nm
(Gree
Argon
514 nm
n)
Krypton
(Blue)
476 nm
(Gree
Krypton
528 nm
n)
Krypton
(Yello
568 nm
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2/16/2016
w)
Krypton
(Red)
647 nm
(White
Xenon
Multiple
)
(Gree
Helium Neon
543 nm
n)
(Yello
Helium Neon
594 nm
w)
(Oran
Helium Neon
612 nm
ge)
Helium Neon
(Red)
633 nm
Helium Neon
(NIR)
1,152 nm
Helium Neon
(MIR)
3,390 nm
Hydrogen Fluoride
(MIR)
2,700 nm
Carbon Dioxide
(FIR)
10,600
nm
(Gree
Metal Vapor Lasers
Copper Vapor
510 nm
n)
(Yello
Copper Vapor
570 nm
w)
Gold Vapor
(Red)
627 nm
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High Energy Lasers
Green, David
2/16/2016
(Gree
Doubled Nd: YAG
532 nm
n)
Neodymium: YAG
(NIR)
1,064 nm
Erbium: Glass
(MIR)
1,540 nm
Erbium: YAG
(MIR)
2,940 nm
Holmium: YLF
(MIR)
2,060 nm
Holmium: YAG
(MIR)
2,100 nm
(Red)
694 nm
Chromium Sapphire
(Ruby)
840-1,100
Titanium Sapphire
(NIR)
nm
700-815
Alexandrite
(NIR)
nm
570-650
Dye Lasers
Rhodamine 6G
(VIS)
nm
(Gree
Coumarin C30
504 nm
n)
Semiconductor
Gallium Arsenide (GaAs)
(NIR)
840 nm
Gallium Aluminum
(VIS/
670-830
Lasers
Arsenide
NIR)
nm
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High Energy Lasers
Green, David
2/16/2016
Work Cited
US Army Space and Missile Defense Command, “High Energy Laser System Test Facility,
03/09/2003,www.smdc.army.mil
Defense Department, “Tactical High Energy Laser THEL system” 03/09/2003, www.defenseupdate.com/directory/THEL.htm
Foundation for Advancement in Science, “Tactical High Energy Laser” 03/07/2003,
www.fas.org/spp/starwars/program/thel/htm
Foundation for Advancement in Science, “Laser Technology” 03/07/2003,
www.fas.org/spp/starwars/program/nssrm/categories/lt.htm
Robert Aldrich, ”Laser Fundamentals”, 03/07/2003, www.fas.org/man/dod101/navy/doc/laser/fundamentals.htm
John Gormally, “Laser Tutorial”, 03/07/2003, http://members.aol.com/WSRNet/tut/tx.htm
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