Converting Photodiode Signal to Laser Power

To determine incident laser power on a photodiode using the voltage from the photodiode (generally as measured with an oscilloscope), use:

$P={\frac {V}{(Amps/W)*(V/Amps)}}$

With $V$ as the potential difference from the photodetector with the laser on/off, and $Amps/W$ and $V/Amp$ as two conversion factors depending on the wavelength of the laser and the gain setting of the detector respectively.