What is the entity for team lasers?
 

Like the kind that protect spawns and such

Trigger_hurt. It's an invisible volume that does damage. You need to have a corresponding lua function so that it only kills one team. Look at another map's lua (like aardvark) for an example.

For the visual effect, use some env_beams or a func_illusionary with the shield texture applied.

as long as you include base_shutdown in your LUA, all you need is a trigger_hurt named red_laser_hurt or blue_laser_hurt and then a func_button called button_red or button_blue to turn the lasers on and off. all the rest is handled for you.

when making the visual effect, don't use env_lasers.
env_beams are better because you can't block them (shutdown2 has this problem ironically). turn them on and off using the onIn and onOut outputs from your func_button.