Long-term instability and irreproducibility of a gas laser frequency and requirements to be satisfied by automatic frequency control systems

An analysis is made of monotonic frequency drifts exhibited by gas lasers with automatic frequency control (AFC) systems. The long-term instability and irreproducibility of the emission frequency are found as a function of the long-term instability and irreproducibility of the reference point and errors of the AFC system. Ways of reducing these errors are considered and the experimental results of the error determination are given. Practical recommendations are made for increasing the long-term stability and reproducibility of the laser frequency by a suitable choice of elements of the AFC systems and of their operating conditions.