Dr. Schilling does not think the laser pistol is as far fetched as most believe. Erik points out that the problem with a man-portable laser pistol would be the power source. Kinetic weapons are probably going to outperform beam weapons for man-portable sidearms for a long time. Luke Campbell has an in depth analysis of laser weapons for science fiction on his website.
But first a safety note. Pretty much zero science fiction stories, movies, or TV shows mention that laser sidearms have the ability to permanently blind anybody closer to the weapon than the horizon. If the beam is in the frequencies that can penetrate the cornea of the eye, and the beam reflects off a door nob or other mirrored surface, anybody whose eyes get flashed by the beam is going to need a seeing-eye dog. There are more details here.
The key to making a laser do bullet levels of damage is pulsing the laser. The first pulse creates a steam explosion and a shallow crater in the skin of the hapless pirate. By careful timing, the second pulse arrives after the steam from the first pulse has dissipated and creates a second crater at the bottom of the first. If you don't delay the pulses, the cloud of steam interferes with laser beam, protecting the target. By altering the variables one can have a laser beam that will penetrate a human body but only bore a little way into metal. As an added bonus, lasers have no recoil.
James Borham notes:
There was discussion about ultracapacitors:
Luke Campbell said:
Elsewhere Luke Campbell said:
I will also note that there currently exists a species of "scope through the gun barrel" piece of gear for conventional slug-throwing rifles, the EOP system.
As it turns out, the Phaser type-I from the classic Star Trek TV show had a reflex aimsight. Turning the dial on the top would raise the acrylic aimsight. This would also work with the type-II pistol phaser, since that incorporates a type-I phaser. You can read about the aimsight here, here, here, here, and here. If you have lots of disposable income, you can purchase a hero movie prop.
James Borham notes:
|Far Infrared||3e-5 to 1e-3 m (30,000 to 1,000,000 nanometers)|
|Mid Infrared||5e-6 to 3e-5 m (5000 to 30,000 nanometers)|
|Near Infrared||7e-7 to 5e-6 m (700 to 5000 nanometers)|
|Red||7.1e-7 m (710 nanometers)|
|Orange||6e-7 m (600 nanometers)|
|Yellow||5.7e-7 m (570 nanometers)|
|Green||5.5e-7 m (550 nanometers)|
|Blue||4.75e-7 m (475 nanometers)|
|Indigo||4.3e-7 m (430 nanometers)|
|Violet||3.8e-7 m (380 nanometers)|
|Ultraviolet A||3.2e-7 to 4e-7 m (320 to 400 nanometers)|
|Ultraviolet B||2.9e-7 to 3.2e-7 m (290 to 320 nanometers)|
|Ultraviolet C||2e-7 to 2.9e-7 m (200 to 290 nanometers)|
|Extreme Ultraviolet||1e-8 to 2e-7 m (10 to 200 nanometers)|
|X-Ray||1e-11 to 1e-8 m (0.01 to 10 nanometers)|
|Gamma-Ray||1e-14 to 1e-11 m (1e-5 to 0.01 nanometer)|
|Cosmic-Ray||1e-17 to 1e-14 m (1e-8 to 1e-5 nanometers)|
Note that wavelengths shorter than 200 nanometers are absorbed by Terra's atmosphere (so they are sometimes called "Vacuum frequencies") and anything shorter than 10 nanometers is considered "ionizing radiation" (i.e., what the an average person on the street calls "atomic radiation").
In the chart below, you can see the vulnerability of various parts of the human body to various laser frequencies. Hemoglobin is blood. Melanin is skin and hair. Water is all body tissue. Scatter is the molecular bonds holding proteins together.
So lets take a hypothetical laser sidearm, assume a 10cm lens, 10kW output power, 1ms beam duration, and 0.5 duty cycle. Given these as constant, but varying the wavelength of the laser, we get the following penetration on a carbon target at the listed ranged:
7e-7 m (Near infrared) Range Penetration 25m 6.25mm 50m 0.78mm 100m 0.10mm 200m 0.01mm 5.5e-7 m (Green) Range Penetration 25m 12.88mm 50m 1.61mm 100m 0.20mm 200m 0.03mm 4.3e-7 m (Indigo) Range Penetration 25m 26.96mm 50m 3.37mm 100m 0.42mm 200m 0.05mm 3.2e-7 m (UVA) Range Penetration 25m 65.4mm 50m 8.18mm 100m 1.02mm 200m 0.13mm
It's obvious that as wavelength decreases, neglecting atmospheric effects, damage on the target increases. So the question is, how low can I push my wavelength, and what are the effects? If 90% of the UVA beam is scattered, then it is equivalent to the infrared beam. If only 50%, it is superior.
Seems like an important point to figure out. Does anyone have a good model? I've been digging on scholar.google.com to no avail.
If one is using this information in order to write an SF novel, the question comes up of what will an observer see and hear during a laser pistol battle. Luke Campbell has the information.
As I already stated, pretty much no science fiction in movies, TV or novels mentions the blindness hazard of laser sidearms (with the possible exception of Jack Williamson's Trapped In Space). On Terra, anybody within about five kilometers (i.e, the horizon) of an operating laser weapon is at risk of loosing their eyesight permanently. If the beam flicks over a window, a shiny automobile, or anything else reflective (reflected or scattered light); an innocent bystander will suddenly require the services of a working dog. People knowingly entering a laser gun battle will be wearing anti-laser goggles (or contact lenses). Laser gunmen who care about innocent bystanders will use lasers of frequencies opaque to the cornea of the eye.
There is a laser safety classification system. Class 1 is safe for eyesight. Class 1M is safe as long as you are not looking at the laser through a magnifying glass or telescope. Class 2 is safe for eyesight due to the human blinking reflex (most laser pointers fall into this catagory). Class 2M is safe with no magnifying glasses or telescopes. Class 3R are mildy dangerous. Class 3B are dangerous but diffuse reflection is not (laser protective goggles required). Class 4 are incredibly dangerous, since it will also burn holes in clothing and skin (laser protective goggles required). Naturally all laser weapons are class 4.
Luke has more details about laser eye damage here. Below is a sample:
Holger Bjerre points out that while such UV wavelengths do not penetrate the eye, they will abrade the surface of the eye. After all, such UV lasers are used for laser-vision correction surgery. Such abrasion may or may not be correctable, but it is damage.
Also note that Protocol IV of the 1980 Convention on Certain Conventional Weapons (issued by the United Nations on 13 October 1995) states:
Of course the U.S. Department of Defense is working on the Personnel Halting and Stimulation Response rifle, which is a laser-blinding weapon intended for crowd control. It is intended to skirt the 1995 UN Protocol on Blinding Laser Weapons by not blinding the target permanently (they hope).
The energy requirements mentioned by Dr. Schilling make it clear that the laser's battery will be carrying plenty of juice. Anything carrying that much energy will be at least slightly unstable. In other words, it wouldn't take much to make a charged battery into a home-made bomb (which might come in handy if one suddenly needed a bomb.). You might have read news reports about laptop computers whose batteries suddenly burst into flame.
And don't even think about sticking a fork into the open contacts.
This has been observed somewhat tongue-in-cheek by John Routledge as Routledge's Law:
He also notes the problem with ammunition cook off. If you are holding a fully-charged laser pistol, and some lucky enemy sniper manages to score a direct hit on the pistol's battery, it is going to be just too bad if the resulting explosion vaporizes you and all your friends within a large radius.
Assuming a worst case of 5 kilojoules per shot and a rechargeable magazine containing 50 shots, the magazine is packing 250 kilojoules. This is the equivalent of 250,000 * 2.7778e-4 = 70 watt-hours or 250,000 / 4,500 = 55 grams of TNT (For comparison purposes, a standard 8 inch stick of dynamite is about 208 grams and hand grenades used by the US Army have explosive charges of 56 to 226 grams of TNT). At his specified power density of 2.5 kilojoules per cubic centimeter, this would imply a magazine volume of 100 cm3. this is approximately the same volume as forty-two .45 caliber rounds.
You may remember that in Star Trek, phaser hand weapons could be set to explode like hand grenades, a "forced chamber explosion."
The above is a reasonble energy magazine. At the extreme end, in L. Neil Smith's BRIGHTSUIT MACBEAR, we find the five-megawatt fusion-powered pistol.
Before laser bullets are developed, you might find laser pistols with separate power sources. In the role playing game Traveller, laser carbines are powered by a large battery worn in a back pack. In the Barbarella comic, deflagrating guns have their battery strapped to the upper leg. Gene Roddenberry's original conception of the Star Trek phasers had a separate waist belt containing several power units. In William Tedford's Silent Galaxy AKA Battlefields of Silence, the hand laser's battery pack is strapped around the wrist.
There was an amusing scene in a remarkably bad '50s movie called Teenagers from Outer Space. The hero unfortunately broke the power pack on his focused disintegrator ray. He manages to cobble together a solution just in time to save the day. He attaches a cable from a nearby high-tension power line, and convinces the power plant to shove the generator output up to maximum!
Some SF novels have postulated one-shot power modules. "Laser bullets" in other words. In Norman Spinrad's Agents of Chaos, laser pistols were a ruby rod with a magazine full of "electro-crystals". Pulling the trigger caused the next crystal in the magazine to release its charge, that is, it was sort of a super-capacitor. Taking this a step further, one can imagine a "laser revolver", with capacitors taking the place of bullets. Don't throw the spent capacitors away, they can be re-charged. A .45 caliber cartridge is about 11.43 mm x 23 mm, which gives it a volume of about 2.4 cubic centimeters. At a rechargeable 2.5 kj/cm3 this means a battery the size of a .45 round would hold a good 6 kilojoules, enough for an extra-strength laser bolt.
In David Drake's Hammer's Slammers novels, the "powerguns" utilized an as-yet undiscovered scientific principle to instantly convert copper impregnated plastic wafers into a high-temperature bolt of plasma traveling at high velocity. Drake said all he wanted to do was postulate some hand-waving way of putting plasma bolts into bullets so he could write about futuristic soldiers.
In the original Star Trek episode "The Galileo Seven", Mr. Scott drains the energy out of a bunch of phaser pistols into the engines of the shuttlecraft. Doing some pointless calculations based on a very unscientific script we can hazard a guess at the energy content of a phaser pistol.
Some website I found claimed that a shuttlecraft was 17 metric tons. Assume that each crewmember is 68 kilos (150 pounds), this adds another 476 kilos for the seven crewmembers. The shuttle doesn't quite make orbit. As an upper limit, to make orbit would require a deltaV of around 8 km/s. Plugging this into the equation for kinetic energy gives us an energy requirement of about 5.6e11 joules. There appears to be six phaser pistols drained, so each phaser contains 5.6e11 / 6 = 9.3e10 joules.
How much is 9.3e10 joules? Well, it is 9.3e10 * 2.7778e-7 = 26,000 kilowatt-hours or 9.3e10 / 4,500,000 = 21,000 kilograms of TNT. Well, let's face it, it takes lots of energy to vaporize an human being with one zap.
This is hysterically out of date.
What about particle-beam sidearms? Well, their minor draw-back is the fact that each shot you fired would have the side effect of exposing you to a lethal dose of radiation. But other than that they would be quite spectacular weapons.
Dr. Schilling mentions above that the conventional way to generate particle beams are with pulsed linear induction accelerators, but these will be difficult to reduce to pistol size. A more radical method of creating particle beams is with wake field accelerators, which produce electron beams on the electric fields of forced plasma waves.
He also mentions that high-current electron beams tend to be self-focusing in air, which simplifies things if you take that route. For ranges much over a hundred meters you have to start worrying about energy loss, which can probably be dealt with. For handguns, it isn't a problem.
You'll need a bit over a kilojoule of output energy to reliably incapacitate a human target, just like lasers. Unlike lasers, you won't have to pulse the beam, just pour it on in one big bolt.
Luke Campbell and Anthony Jackson got into a discussion of this. Alas it is over my head like a cirrus cloud.
Apparently an electron particle beam would resemble a lightning bolt.