If so, what are the limitations compared to traditional rifles? Maybe one day, but battery technology is far behind the technology needed to make high power laser pointer rifles practical. Another problem is that if the laser is emitted when it is raining, snowing, or when there are many particles in the air in general, its effectiveness will be significantly reduced. This means that the laser rifle is only effective when the weather is good, which is obviously not ideal.
What is the lowest laser MW that is bright enough to be visible but not enough to damage eyesight? The lowest power you can reliably see is equivalent to a sixth magnitude star. If you shine the light beam directly into your eyes from a peripheral angle of view so that it falls on the rod in your eyes, your dark-adapted eyes should be able to reliably see 5E-16 watts of green light.
If you say that you see the “beam” because you can see the Rayleigh scattering in the air, in the dry air at a height of 5500 feet, I can see the green green laser of 15 milliwatts well in 2003, so I imagine , According to the air density, you can see the scattering of the 10 mW beam at sea level. Even if you blink, 10 mW definitely exceeds the maximum safe power. Note: It is illegal to launch a 10 mW green laser into the sky in an unrestricted airspace. This is done at night at an air force base with limited air space, and be careful not to irradiate the light beam to the Sunport.
So in the final analysis, if you want to see scattered beams in the air, you actually need a blue laser pointer that is not very safe. That is for the green laser. Due to the eye sensitivity curve, blue or red lasers are more difficult to see at the same power level, even if blue is more easily scattered by the atmosphere. You may need a 25 mW blue laser and a 60 mW red laser to see the “beam”.
Kinetic energy weapons like giant railguns require shipboard reactors. But if you want to generate all this energy, why not use energy weapons? It is more flexible, you have no ammunition limit, and energy projectiles may be more effective against protected and unprotected objects than kinetic energy projectiles. I know that hypervelocity railguns can cause devastating damage, but you can also inject the same energy into a laser or plasma bolt. (And usually, railguns need to build spacecraft around them.)