electronics and industrial supply places, you can rip it off a diode based laser cutter but they're very chonk, if you're handy, you'd get just the diodes, lens and then make your own PCB with powersupply. You need adjustable because the light has to be in focus at the distance between you and the camera or else it will be to diffuse to disable the sensor, both too short and too far. You don't really need a galvo head in this case just mount the pcb on something that can randomnly vibrate the laser in a small radius at the effective distance. You won't be able to hit the camera sensor steady, you need to paint over it randomnly, with the right focus it will work even on rare occasionnal hits since those sensor are very sensitive to laser light