The double bulb rubidium maser

The proposed design of a new ⁸⁷Rb maser frequency standard is presented. This device is expected to perform similarly to a hydrogen maser at short and moderate averaging times. An operating maser of this design would much be more compact than a full size hydrogen maser (the cavity need only be ~6 cm in length and diameter). It should also be much less expensive to build. Optical pumping techniques are used to produce a nearly complete population inversion in an evacuated wall coated cell. The population inversion is produced in a cell separated from the microwave interaction region to eliminate problems with light shifts. Since no buffer gas is used the atoms are free to travel through an exchange tube from the optical pumping region to the maser interaction region where oscillation can take place. The system will be completely closed-cycle since atoms will return from the maser region to the optical pumping region where they will be repumped. This eliminates the need for a vacuum system, greatly simplifying operation. The principles of operation and the basis of the stability estimates are discussed