The Fine Structure of the Sharp Series Triplet -2P(0,1,2) - TRIPLET-2S(1) of Optically Excited Mercury Radiation.

Marc Smiciklas, David Charles Shiner

Robert Williams Wood

Edgar J. Murphy

Veniamin V. Tsyplenkov, V. N. Shastin

Abstract The relaxation rates of lower excited states 1s(T), 2p0, 2s, 3p0, and 2p± of arsenic donors in a germanium crystal are calculated upon the interaction with long-wavelength acoustic phonons depending on the uniaxial stress in the crystallographic direction [111]. The populations of states under optical excitation are estimated for calculated times. It is shown theoretically that optical excitation of the medium forms an inverse population of arsenic donor levels and leads to the possibility of the implementation of a four-level laser scheme with the radiative transition between 2p states and the 1s triplet state at zero strain. The estimated value of the expected gain in the medium under optical excitation conditions by CO2 laser radiation in the medium at a donor concentration of 2 × 1015 cm–3 is ~0.35 cm–1 at a frequency of 1.98 THz if the laser transition is 2p± → 1s(T) and 1.25 THz if the laser transition is 2p0 → 1s(T).

J G Lambourne, Francis Jean Penent, P. Lablanquie +9 more

The asymmetry parameter β for fluorescence photons emitted during the radiative decay of the sp2, n +( 1 P o ), sp2, n −( 1 P o ), 2p n d( 1 P o ) and 2p n d( 3 D o ) series of helium doubly excited states, formed by the absorption of linearly polarized synchrotron radiation, has been measured. The results are compared with recent theoretical calculations (Žitnik et al 2002 Phys. Rev. A 65 032520). At high n the β parameter is shown to increase and oscillate due to the excitation of triplet states, optically accessible from the helium ground state due to spin–orbit effects.