Is the laser diode the NUBM08? If so, that diode can be pushed to 3.5 amps without much worry, that is, as long as you have enough heat sink to handle the increased amount of heat it will produce,or limit the run time to keep the diode and target from getting too hot. From what you wrote the laser diode is probably heat sinked very well, but I don't know how much extra power the phosphor can handle, if someone does, I'm curious too. You can find more information about that diode here: NUBM08 455nm 4.3W Laser Diode - DTR's Laser Shop (google.com)
From Manufacturers Datasheet:
- Wavelength: 450nm
- Optical Output: 4.3W @3.0A
- Max. Operating Current: 3.5A
- Typical Operating Voltage: 4.5-4.9V
- Operating temperature 0 to 70 C.
- Typical life is 20,000 hours if run within specified limits with a 1 percent failure rate at 1000 hours.
Many diodes can be pushed a bit higher than the maximum recommended operating current but doing so increases the diode temperature. In general, each 10 degrees C. increase of temperature reduces the life by half but increasing the current too far will cause the diode to fail immediately or in a very short amount of time. To set the current at maximum, without regard to the reduced life in hours, use a laser power meter to see the laser diode output power increase as current is increased, at some point you will reach what is called the *knee where further increase of current does not increase the output power, at that point back the current down by about ten percent to stay under the knee (The *knee typically above 4.5 amps, but I'd limit the current to 4 amps max @ 5.8 watts output/REDUCED LIFE).
Adjusting the current to the driver while the diode is on can cause the diode to fail, not always, perhaps not usually, but can. I often choose the safer method and move the potentiometer adjustment in baby steps, turning the power off to the driver (or disconnect one of the two wires from the battery or DC power supply to the driver), adjusting the current potentiometer, and then turning the driver back on. There are circuits you can build to adjust the driver current without having the laser diode attached, and once set, then attach the laser diode.
Increasing the current above the maximum recommended reduces the life of the diode, go too far and it ends right there. I am not familiar with the driver you mentioned, I always use BlackBuck drivers, I prefer the BB8M which can handle up to eight amps with additional heat sinking, I believe 3 amps without adding a heat sink to the regulator chip: BlackBuck 8M Laser Driver(Buck) - DTR's Laser Shop (google.com)
Note: I can answer some questions about laser diodes, but not LEP's as I am still learning the basics about them. I am not associated with the DTR laser parts store, but I've been a customer for near ten years now.
Warning: If using a cheap "lab" power supply, when turned or switched on, many of them will put out a voltage spike which can kill a laser diode immediately. Also, the power supply must have current limiting built in and adjusted to assure you cannot go higher than the diode can take. Laser diode drivers are protecting the diode by doing just that, setting the current to a maximum amount to the diode.