Omss Science: Function of Raygun

Ray guns as described by science fiction do not have the disadvantages that have, so far, made directed-energy weapons largely impractical as weapons in real life, needing a suspension of disbelief by a technologically educated audience:

Ray guns draw seemingly limitless power from often unspecified sources. In contrast to their real-world counterparts, the batteries or power packs of even handheld weapons are minute, durable, and do not seem to need frequent recharging.
Ray guns in movies are often shown as shooting discrete pulses of energy visible from off-axis, traveling slowly enough for people to see them emerge, or even for the target to evade them, although real-life laser light is invisible from off-axis and travels at the speed of light. This effect could sometimes be attributed to the beam heating atmosphere that it was passing through.^{[citation needed]}. A possible evasion tactic is dodging the firing axis of the gun, theorized in the early story of Mobile Suit Gundam by the character Char Aznable when he first encountered the series protagonist's machine's beam rifle and seemingly dodging it without any difficulty.

Some of the effects are what would be expected from a powerful directed-energy beam, if it could be generated in reality:

Ray guns are often shown as transmitting heat, as with Wells' heat rays.
Ray guns may be used to cut through hard materials like a blowtorch.

But sometimes not:

In movies, rays are often depicted as having effect instantaneously, with a touch of the beam sufficing for the intended purpose. Raygun victims are generally killed instantaneously, often – as in the Star Wars films – without showing visible wounds or even holes in their clothing.
Some rayguns cause their targets to disappear ("de-materialize", disintegrate, vaporize or evaporate) entirely, personal equipment and all.
Occasionally a raygun is shown as transmitting cold, as with the "freeze rays" in the TV series Batman (1966–1968) and Underdog (1964–1970).
Visible barrel recoil. This would only happen if the momentum of the beam were comparable to that of a bullet shot from a gun.
A wide range of non-lethal functions as determined by the requirements of the story: for instance, they may stun, paralyze or knock down a target, much like modern electroshock weapons. Many of the more implausible functions are almost farcical and involve transmutation of matter such as rayguns that age or de-age people (various cartoons), or shrink rays (Fantastic Voyage, Honey, I Shrunk the Kids)

Ultimately, rayguns have whatever properties are required for their dramatic purpose. They bear little resemblance to real-world directed-energy weapons, even if they are given the names of existing technologies such as lasers, masers, or particle beams. This can be compared with real-type firearms as commonly depicted by action movies, as tending infallibly to hit whatever they are aimed at (when wielded by the heroes) and seldom depleting their ammunition.

"FX-Ray laser" in American science fiction and animation is a humorous name for a raygun that shoots a visible beam: "FX" is a show business term for special effects. (Google search for uses)

Rayguns by their various names have various sizes and forms: pistol-like; two-handed (often called a rifle); mounted on a vehicle; artillery-sized mounted on a spaceship or space base or asteroid or planet. The pistol form is seen most often.

Rayguns have a great variety of shapes and sizes, according to the imagination of the story writers or movie prop makers. Most pistol rayguns have a conventional grip and trigger, but some (e.g. Star Trek: The Next Generation phasers) do not. The shapes of some rayguns are influenced by an opinion that they look most effective and weapon-like if they look somewhat like real guns; others, such as this, are not:

V-Gun from the Macross scenario: industrial look.
"Plasma blaster": nuclear laboratory equipment look