A pulse laser emits a very high power beam of laser light with a duration of about a millisecond. Against soft material like flesh, the high intensity light will flash the material to vapor with sufficient violence that it will rip out a cavity in the material, flaying flesh from bone. The light beam propagates through the now-transparent vapor to the back of the expanding cavity, producing more high pressure vapor from the moving interface to drill deep into meat and organs. Incident on hard materials, the beam melts a thin layer and evaporates the surface of the melt. The high pressure evaporate jetting from the molten surface pushes on the molten layer, acting like a piston to squirt the melt layer out along the sides of the hole and producing a spray of incandescent sparks. Since melting is more efficient at removing material than vaporization, this improves the efficiency of the beam at drilling through armor. At longer range, the beam is too diffuse to cause the pulsed vapor explosion, but it still acts like a heat ray, causing melting, charring, and ignition.
In game terms, the pulsed vapor explosion is treated as tight beam burning damage, while the radiant heating is burning damage using the usual rules for damage fall-off as described in the main laser page.
The closer the range to the target, the more tightly focused the laser beam will be when incident on the target. This allows better penetration of hard materials at closer ranges. At less than half the 1/2 D range, apply a (2) armor divisor to the tight beam burning damage (not to the burning damage). At less than one quarter the 1/2 D range, the armor divisor increases to (3). Alternately, consult the table below:
Fraction of ½D range
Armor Divisor*
1
(1)
0.5
(2)
0.25
(3)
* DR after applying armor divisor is never less than the mass-derived cover DR.
This Armor Divisor only applies to DR due to material toughness, strength, and general resiliance; not to sheer mass getting in the way. Hence, do not apply the armor divisor to cover DR determined from an object's HP.
For military purposes, pulse lasers only have adequate range when they emit shorter wavelength beams than the default 1.5 μm near infrared. Consequently, military lasers are at a risk of causing severe eye damage to unprotected bystanders and all soldiers will be issued flash protection goggles. At short range, the high armor penetration of lasers makes them useful against heavily armored troops, while at long range the high accurace of lasers allows them to target lightly armored or unarmored locations on armored adversaries and enables precise long range sniping against unarmored targets. Eye-safe lasers may be used for close-quarters combat such as hostage rescue situations or clearing buildings or vehicles. Civilian lasers use eye-safe wavelengths. Since animals typically do not have significant armor, a pulse laser with a large focusing aperture can harvest game at respectable distances. For civilian self defense, where most attackers are unarmored and engaged at relatively close range, the low recoil and high accuracy of lasers makes them in demand. Pulse lasers tuned to green or blue wavelengths allow superior underwater performance, and are often seen at higher tech levels where other weapons have made pulse lasers obsolete for atmospheric or vacuum engagements.
Two-photon absorption will rapidly attenuate ultraviolet pulse beams at tight focus in air. This gives the shooter the choice of causing reduced damage, or intentionally defocusing the beam to keep the intensity (and hence the two-photon absorption) down to a more reasonable level. The table below gives the damage penalty for beams at full focus
Damage of Ultraviolet Beams at Various Atmospheric Densities
Beam Color
Atmospheric Density
Superdense
Very Dense
Dense
Standard
Thin
Very Thin
Trace
UV-C
1⁄10
1⁄8
1⁄4
1⁄4
1⁄4
1⁄2
full
UV-B
1⁄4
1⁄3
1⁄2
1⁄2
1⁄2
2⁄3
full
UV-A
1⁄3
1⁄2
2⁄3
2⁄3
2⁄3
2⁄3
full
For every "steps" by which the laser is defocused (e.g. going from (3) to (2), or from (1) to beyond 2×½D range), you can get to one step better damage loss following the progression
1⁄10,
1⁄8,
1⁄6,
1⁄4,
1⁄3,
1⁄2,
2⁄3,
full damage.
Visible or infrared light cannot cause two-photon absorption, and thus can ignore this section. A consequence of all this is that ultraviolet pulse lasers are more useful in space combat than on the ground. When ultraviolet beams are used in atmosphere they make an eerie blue-violet beam, faint and whispy near the gunner but increasing in brightness as it nears its focus, with a pungent after-odor of ozone.
Pulse lasers are a late TL 9 technology. Early TL 9 will still be using laser heat rays. TL 9 lasers are still relatively underpowered and bulky, and are relegated to specialist roles. Lasers see substantial improvements into TL 10, where they become widely used.
