Use high voltage but low capacitor values to get short flash duration. It really does not matter for photography (us vs ns) but for lasers you need to pump as much energy as possible in the first few ns time scale.
Always keep some headroom, if the flash tube is rated at 100J, do not use more than 50J (or even less) per pulse (with a very low pulse rate). Remember than 1J/1us is only one MW in power. Laser excitation efficiency is usually low but if you get 10% conversion, consider that excellent.