Time-dependence of the Frequency and Line-width of the Optical Emission from a Pulsed Ruby Maser

Abstract

THE theoretical and practical interest in the sharpness of the spectral lines from a pulsed ruby optical maser prompted us to make an interferometric study of its emission1. This investigation revealed that a surprisingly large number of narrow frequency components were produced, even with power input very close to threshold. Fig. 1 shows an interferogram taken with a 40-cm spherical Fabry–Perot etalon2, having a resolution of 2–3 Mc/s. The question of the origin of these many narrow frequency components, emitted during a single pulse from the flash lamp, has been unambiguously answered by the time-resolution studies reported here. The results have also revealed several new features of ruby maser emission. For these experiments, time resolution was obtained by adding to our apparatus a 1P25 image tube with a linear magnetic time sweep. The ruby crystal was 0.4 × 0.4 cm and 6cm long, silver coated (4 percent transmission), and immersed in liquid nitrogen. The flash lamp was designed to minimize the magnetic field at the crystal.