Gas laser output opto-magnetic stabiliser - uses optically derived signal for magnetic field control which affects discharge channel strength

摘要

The variations of the output power of a gas laser are caused by the gas discharge mode and the variations of the current supply. Instead of using an acousto-optic transducer in the laser resonator, a signal derived optically from the laser output power is used for control of a magnetic field, affecting the discharge channel. A magnetic coil (1) is wound round the laser tube (6), containing the discharge channel (4). The assembly is mounted in the resonator between mirrors (5). The output power proportional signal is generated in the photodetector (2) from the Brewster window reflex beam (7). Alternately the beam (8), leaving the resonator, may be used for this purpose. The current from the photodector is supplied to an electronic control circuit (3) generating the control current.