ルビー光メーザーの発光パターン(続報)

抄録

The relation between the optical quality of a ruby rod and the oscillation pattern was reported in the preceding paper in which a mention was made that, even with a plane parallel rod, many kinds of patterns, rings and Lissajous', were observed in a train of spikes taken with a high speed streak camera. As a continuation of the work, the case of a uniform rod with ununiform distribution of refractive index, whereby the light path in the rod is not straight, is dealt with.
On the assumption that the refractive index varies as n=n₀(1-ax²-by²) and that the laser action occurs when the light path is closed after repeated reflections, the number of spots that the oscillation pattern comprises and the type and dimension of the far-field patterns are explained. The light from the rod is not of a simple wave front; it is composed of many light bundles which fact is proved by covering the rod end with a semi-circular aperture: it merely reduces the light but does not change the far-field patterns. Furthermore, it is observed that one light bundle is about 0.3 mm in diameter in the rod.
By this analysis, the dimensions of near-field patterns can not be determined; they are considered to be affected by the distribution of excitation.