Ruby as a Maser Material

The reasons for the initial choice of ruby as a maser material are outlined and some measurements of the parameters in the spin Hamiltonian and of spin relaxation times are reported. The relative merits of single‐ and double‐pump modes of operation of a four‐level maser are discussed and measurements of the oscillator power for the two cases are included.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70658/2/JAPIAU-30-7-1061-1.pd