Optical pumping of microwave masers

The application of optical pumping techniques to microwave masers is discussed. It is shown that optical pumping appears to be promising for achieving low noise maser action at very high frequencies and at elevated temperatures. The analysis includes the treatment of optical pumping principles, noise considerations, pump power requirements and maximum signal frequencies. Potential advantages and limitations which can exist when using optical excitation are considered. Finally, the concepts and procedures developed in this paper are applied for illustrative purposes to evaluate the expected performance of a ruby maser.