What you really want is a shutter
picture borrowed at a possible source:
http://www.laser2000.co.uk/laser_accessories.php?Category=93
where each shutter (shown in the link) needs 700mA
So you need 4 digital outputs, and if your outputs can't driver that current an additional 5V power supply, 4 resistors (1k) and 4 transistors and 4 diodes to protect the transistors....
And these shutters run in safety mode: If not powered they shut the laser beam by spring load.
Greetings from Germany
Henrik
LV since v3.1
“ground” is a convenient fantasy
'˙˙˙˙uıɐƃɐ lɐıp puɐ °06 ǝuoɥd ɹnoʎ uɹnʇ ǝsɐǝld 'ʎɹɐuıƃɐɯı sı pǝlɐıp ǝʌɐɥ noʎ ɹǝqɯnu ǝɥʇ'