Raman stimulated neutrino pair emission

A new scheme using macroscopic coherence is proposed to experimentally determine the neutrino mass matrix, in particular the absolute value of neutrino masses, and the mass type, Majorana or Dirac. The proposed process is a collective, coherent Raman scattering followed by neutrino-pair emission from | e of a long lifetime to | g ;.0 + | e .. + i j.i. j + | g with.i. j consisting of six massive neutrino-pairs. Calculated angular distribution has six (i j) thresholds which showup as steps at different angles. Angular locations of thresholds and event rates of the angular distribution make it possible to experimentally determine the smallest neutrino mass to the level of less than several meV, (accordingly all threemasses using neutrino oscillation data), the mass ordering pattern, normal or inverted, and to distinguish whether neutrinos are ofMajorana or Dirac type. Event rates of neutrino-pair emission, when the mechanism of macroscopic coherence amplification works, may become large enough for realistic experiments by carefully selecting certain types of target. The problem to be overcome is macro-coherently amplified quantum electrodynamic background of the process,.0 + | e .. +.2 +.3 + | g , when two extra photons,.2,.3, escape detection. We illustrate our idea using neutral Xe and trivalent Ho ion doped in dielectric crystals

Periodic super-radiance in Er:YSO crystal

We observed periodic optical pulses from an Er:YSO crystal during irradiating with an continuous-wave excitation laser. We refer to this new phenomenon as "periodic super-radiance". This periodicity can be understood qualitatively by a simple model, in which a cyclic process of a continuous supply of population inversion and a sudden burst of super-radiance is repeated. The excitation power dependences of peak interval and the pulse area can be interpreted with our simple model. In addition, the linewidth of super-radiance is much narrower than an inhomogeneous broadening in a crystal. This result suggests that only Er3+ ions in a specific environment are involved in super-radiance.Comment: 7 pages, 5 figure

Multi-layered flyer accelerated by laser induced shock waves

Copyright 2000 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Physics of Plasmas, 7(2), 676-680, 2000 and may be found at http://dx.doi.org/10.1063/1.87385

Frequency dependence of coherently amplified two-photon emission from hydrogen molecules

We investigate how the efficiency of coherently amplified two-photon emission depends on the frequency of one of the two emitted photons, namely the signal photon. This is done over the wavelength range of 5.048-10.21 mu m by using the vibrational transition of parahydrogen. The efficiency increases with the frequency of the signal photon. Considering experimental errors, our results are consistent with the theoretical prediction for the present experimental conditions. This study is an experimental demonstration of the frequency dependence of coherently amplified two-photon emission, and also presents its potential as a light source