IR laser diodes, especially a 200mW one, are not very well suited for lighting a large enough area for night vision. At the most you will just have a IR spotlight. IR LED's would work a lot better for you.
It hasn't got to light up a large area it just needs to be like a tight spot say a5 foot circle at 40 to 50 yards the illuminators on the market are about 150 pounds an I have built a few lasers an thought it would be a cheap alternative all the best ADE
You don't have to mess a working laser for that. A 780nm diode from an old 40x CD writer will be enough. For some reason my camera gets better that 780nm than those 808nm used to pump dpss'
Iv done it all I have done is use one of those cree zoom torches as a host it had packed in and took the internals out of the pen took the cristal off replaced the lens drilled a hole through the star for the laser housing to fit into powered it with a cr123a an compared to my mates illuminator its not much different apart from 120 pounds an I paid 3.99 an a bit of work atb ADE