Patent ID: 8731014

Claim:
Laser apparatus including a laser energized by an output of an energy source, wherein the laser output-power is stabilized by periodic adjustment of the output of the energy source, the invention comprising: a detector arranged to receive a sample of the laser output and generate in response a voltage signal representative of the laser output-power; an amplifier arranged to amplify the voltage signal generated by the detector, the amplifier having an offset-voltage characteristic that is temporally variable depending on temporal variation of the operating parameters of the amplifier; electronic circuitry for measuring the amplified voltage signal from the amplifier and making the periodic adjustment of the output of the energy source responsive to a corresponding periodic measurement of the amplified voltage signal and a stored value of a specified, output-power of the laser, said electronic circuitry canceling-out an instant amplifier offset-voltage from the amplified voltage signal prior to each periodic adjustment of the output of the energy source; and wherein the electronic circuitry includes a switch operated by the electronic circuitry for disconnecting the detector from the amplifier prior to making the periodic adjustment of the output of the energy source and re-connecting the detector to the amplifier after making the periodic adjustment of the output of the energy source.