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Mode Characteristics and Coherence in Optical Ruby Masers

Naturevolume 192pages957959 (1961) | Download Citation



AN optical maser, using a good-quality ruby crystal with plane-parallel reflectors, oscillates in modes corresponding to Fabry–Perot resonances. Oscillations are shown to occur at several different wavelengths corresponding to various numbers of half-wave-lengths between reflecting ends. For each wavelength, there are many angular modes which are coupled so that they oscillate coherently. This implies that a set of angular modes may be considered a single modified mode and that light from the entire set may be focused to a point of minimum size allowed by the wave-length of the light.

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  1. Columbia University, New York

    • I. D. ABELLA
  2. Massachusetts Institute of Technology, Cambridge, Mass.

    • C. H. TOWNES


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