Nature of the Phonon Beam Emitted by the Ruby Saser
L. G. Tilstra；A. F. M. Arts；H. W. De Wijn
Chinese Journal of Physics
|Volume or Term/Year and Month of Publication||
49卷1期（2011 / 02 / 01）
184 - 190
The properties of the phonon beam emitted by the optically pumped ”hot zone” in the ruby saser are examined. The phonons generated are detected via the R1 luminescence and analyzed by the use of coherent Bloch-type equations. The phonons are found to reach occupations p of order 3000, which at the relevant phonon frequency of 50.4 GHz corresponds to temperatures of order 5000 K. The spectral and angular distributions of the beam have been measured in experiments involving pumped zones at either end of the crystal, one serving as generator, the other one as detector. The spectral distribution is 54±10 MHz wide at half value, or 0.1% of the phonon frequency. Within errors, this is in conformity with the inhomogeneous Gaussian frequency spread inherent to the sasering one-phonon transition. The angular divergence appears to be governed by the geometry of the hot zone. Under the prevailing conditions it measures 3 degrees of arc to either side.