Key points are not available for this paper at this time.
The characteristics of phonon-terminated coherent oscillation associated with Ni^2+, Co^2+, and V^2+ ions in rutile and perovskite fluorides are described. Continuous tunability over portions of the vibronic continuum of Ni^2+ in MgF₂ has been demonstrated. The system has been thermally tuned in discontinuous segments over a total wavelength span from 1. 62 to 1. 80, the longest continuous segment being 250 (82 cm^-1). Alternatively, a frequency-selective element (prism) has been used to vary the oscillation frequency (at a fixed temperature of 85^) in discontinuous segments between 1. 62 and 1. 84. The discontinuities are a consequence of structure present in the vibronic continuum of Ni^2+ in MgF₂. Continuous-wave oscillation has been obtained from Ni^2+ ions in MgF₂ and MnF₂, requiring, respectively, less than 65 and 240 W of power into a tungsten lamp. Both systems display continuous spiking, and the spectral distributions of maser emission may be very complex.
Johnson et al. (Fri,) studied this question.