The idea is for a researchable new type of missile that is less vulnerable to PD by being able to attack ships at short range instead of impacting them. Instead of detonating the warhead against the hull/shields of enemy ships, some kind of containment field is used to channel the detonation energy into a one-time use laser pump that is then fired at the target ship.
In game terms, instead dealing damage when the missile collides with it's destination, once it gets into short range it explodes and fires a number of laser weapon shots at the missile's target. The laser used depends on which laser and missile techs you have researched:
- lasers + guidance systems -> nuclear-pumped laser missile
- turbolasers + fusion warheads -> fusion-pumped laser missile
- primary beams + antimatter warheads -> antimatter-pumped beam missile
These are in addition to the core pumped laser warhead tech (see below). Researching the corresponding laser tech probably should unlock new versions of this weapon, for consistency with the way new types of regular missiles become available.
The number of shots made can be used to balance the damage output of the missiles. I currently envision the weapon as an alternative to regular missiles that is less vulnerable to PD, so I would set the number of shots so that the average damage output is roughly the same as the corresponding missile warhead, but of course that can be changed according to the needs of game design.
The research requirements would probably be something like: corresponding missile tech + corresponding laser tech + either containment fields or a new tech that has it as a prerequisite, depending on how much research you think it should need to acquire.
This idea could alternatively be an alternate type of torpedo instead of missile, but I think that runs counter to the idea of it being a way to mitigate PD.
Edit: Actually I can see this potentially as a torpedo tech - while torpedoes trade vulnerability to PD for more raw damage, this tech could then be researched as a way to address that downside of torpedoes.
In that case then the tech requirements would be: (corresponding laser tech) + (corresponding torpedo tech) + (the core laser pumped warhead tech as described above)
Edit2: And while short range isn't that big a deal for missiles, it matters more for torpedoes that would take longer to cross that short range (I chose short range since it is the range at which lasers do not suffer attenuation).