What resistor do I need to turn a 6 volt current into a 5 volt current?
Because the current need of the laser unknown, it is better to drop the voltade with a 1N4007 Diode, it drops the voltage by 0,7v to 1,0 volt depending on the current draws by the laser. Anode connect to + of bettery, Cathode to the Laser (+) terminal.