For the sake of notekeeping, I'll review what we previously discussed over Skype.
As there are several types of lasers - infrared, visible light, UV and different effects for each - there are also different types of methods for generating the lasers to begin with. IIRC, this includes solid state, free electron and finally of most interest to you, chemical. A chemical based laser more or less uses the reaction between several volatile, well, chemicals to generate the laser. This is potentially of interest to you because, if you wanted, you can just swap out the disposable capacitors for spess-powder to be used in conjunction with the good, old fashioned black powder. The reason for this is that, well, capacitors are still likely to be more expensive.
If you want to make this change to the design, well, it's no hurry.