So, what are the main problems with directed energy weaponry?
1) Energy requirements - lasers are terribly inefficient, where 10% productive output and 90% waste heat is a very good result. Thus, they require a lot of energy
2) Heat management. Mainly because of the previously mentioned amounts of waste heat, lasers require cooling. Well, not really, if we take
modern day lasers, but in-universe for some reason.
3) Energy bloom, dispersion, difraction. Unlike mass accelerators, energy weapons are limited by the fact that they effectively strike not just the target, but everything in-between the shooter and the target, wasting shot's energy on the medium between the target and the muzzle of the weapon. In atmosphere lasers above certain power ignite plasma along the laser channel, which starts screening the further laser emission. effectively this means that in smoky or misty conditions, lasers are far less efficient than normal.
3b) Radiation bloom, which is the bain of hard radiation weaponry (in atmosphere).
Raylegh's scattering is proportional to the fourth power of the lightwave's frequency. This means that for a laser that has the wavelength two times shorter, the losses due to said scattering will be 16 times higher. It also presents a danger to the shooter itself, as the radiation bloom will reach backwards (see the intensity of the scattered beam).
So, how can those be overcome?
1) Energy efficiency. We can come up with more energy-efficient lasers / light-based weaponry somehow, through the miracle of advanced materials.
2) More oomph for less energy. The point of the weapon is to inflict damage. Hard radiation weaponry is much more effective than heat beams, for example, thousands of times more efficient, in fact. The instantly (within minutes) lethal dose of radiation is 10 Gr, that is 10 Joules per kilogram of weight (i.e., if vital organs, such as brain, are targeted, than barely anything at all). This shifts the light-based weaponry's role from the weapon of soldiers on the battlefield, to the concealed weaponry of assassins (because low powered hard-rad weapons used to give osmeone lethal radiation poisoning can be made small and concealed and used without anyone noticing). How to get hard radiation weaponry? I already mentioned blue-shift. This cn be something to be investigated (especially given how useful it is opverall and what else it can be used for, blueshift is soemthing we need to look into anyway).
3) Heat management. Here, I think, I have an interesting idea. Again, mass effect and blue/red shift. Heat is
transferred, through three channels: radiation, conduction, convection. For all of them, mass effect can be used to increase the efficiency of the cooling system:
3a) Conduction. Heat is energy of the vibrating molecules. When two bodies are in contact with each other, the molecules on the surface of one body interact with the molecules on the surface of the second body, transferring their vibrational energy to them (from the heated body to the cooled body). If the mass of the molecules of the colder body is bigger, than they are heated less (simply because it would require more energy to make them move faster). Thus, either placing the casing / radiators into the mass-increasing (from here on out "positive") ME field, or the heated body into the mass-lowering (negative) ME field, would increase the efficiency of the a "heat capacitor" type of the cooling system (that is a large cold body that is used to store the heat from the heated body).
3b) Radiation. Energy of each photon is directly proportional to its frequency. This means that a photon of an EM wave with the wavelength two time longer than a given one, would have two times less energy. Thus, if the main source of heating is radiative heat (such as the heat from a plasma discharge, like the ones used in many
gas lasers) was to be placed into a positive ME field, and the heat receptor was to be placed into the negative ME field, the energy of photons actually getting to the radiator would be less, resulting in the lower temepratures and less heat to manage
3c) As can be seen above, 3a and 3b offer diametrically opposed solutions for heat managing problem. Which solution to use where is a question for engineers. For example, in space, 3b would be more useful, as there radiation is the domineering mechanism of heat transfer. However, both of them can be actually combined. As many of you know, hard radiation easily pierces solid bodies and requires thick shielding to be used. This is because the cross-section of high-energy gamma-quants/solids interactions is small. That is, it is unlikely that high energy photons would interact with a solid body, but it is more likely that they will pass clear through it, without dissipating their energy into it. Thus, a layered solution exists. A layer of heat-conducting transparent material (with systems to transfer heat out, like water circulation cooling) in immediate contact with the heated object under the effects of a positive (relative to the heated object) ME, encased in a layer of EM-absrobing (including in the radio-wave wavelength) material under the effects of the negative ME would be the optimal solution covering all the bases.
3d) Speaking of, carbon is magic. The best known heat conductor is diamond. So, a diamond casing with eezo doping layers and channels for water might be a good way to make the heat dissipation system.
4) Energy bloom, dissipation, difraction and ionization of air, as well as Raylegh's scattering all stem from one problem - there is a gaseous medium between the weapon and the target. This can possibly be dealt with by marrying mass accelerator to the directed energy weapon, and pre-cleaning the path for the beam by shooting a high-speed projectile through it. It would require good timing, though, for it to work, and a pulsed weaponry. on the plus side, in vacuum those things shouldn't be a problem at all, as well as in really close spaces, i.e. in the conditions of space warfare and ship boarding.
