Letter | Published:

Microwave Inversion Efficiency of Orange Ruby

Naturevolume 199pages898899 (1963) | Download Citation



RECENTLY some ruby, grown by a vapour-phase process, has been found to be orange coloured rather than the normal pink. Some of this has been investigated as a potential maser material by taking a small sample ( 10 mg), containing 0.05 per cent Cr3+, double pumping at 23 kMc/s and observing the resulting inversion of the 2–3 transition at 9 kMc/s (Fig. 1). This was then compared with the inversion obtained from a sample of pink ruby of similar size and concentration, placed in the microwave cavity, alongside the orange ruby. The c axes of the two crystals were arranged to be at 90° to each other and at 45° to the radiofrequency magnetic field in order to achieve similar transition probabilities. The inversion ratio I, defined as: when measured at 1.4° K, was found to be 1.5 for the pink ruby, while that of the orange was much bigger, being of the order of 5.0 for most samples.

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  1. 1

    Weber, J., Rev. Mod. Phys., 31, 681, appendix (1959).

  2. 2

    Scovil, H. E. D., Feher, G., and Seidel, H., Phys. Rev., 105, 762 (1957).

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  1. Royal Radar Establishment, Malvern, Worcestershire

    • D. G. JOLLEY
    •  & S. D. MCLAUGHLAN


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